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African rice (Oryza glaberrima): History and future potential
Abstract
The African species of rice (Oryza glaberrima) was cultivated long before Europeans arrived in the continent. At present, O. glaberrima is being replaced by the introduced Asian species of rice, Oryza sativa. Some West African farmers, including the Jola of southern Senegal, still grow African rice for use in ritual contexts. The two species of rice have recently been crossed, producing a promising hybrid.
... Two species of rice plants have been identified in GB since colonial times, Oryza glaberrima and O. sativa. The first is a species native to Africa, where farmers have been domesticating and selecting varieties for 2000 and 3000 years [16,18,19,79]. In contrast, O. sativa is a species native to Asia and was introduced by the Portuguese and/or the Arabs during the colonial period in the 17th century [16,21]. ...
... The first is a species native to Africa, where farmers have been domesticating and selecting varieties for 2000 and 3000 years [16,18,19,79]. In contrast, O. sativa is a species native to Asia and was introduced by the Portuguese and/or the Arabs during the colonial period in the 17th century [16,21]. These species have significant advantages and disadvantages in terms of their adaptability to the MSRPS ( Table 2). ...
... Rice varieties may be classified based on the crop cycle duration: short-cycle varieties (>90 days after sowing (das)), medium-cycle varieties (115-125 das), and long-cycle varieties (>135 das) [16,21,25,65,79,81,85]. This depends primarily on the rice species, as O. glaberrima varieties tend to have a shorter growth cycle compared with O. sativa varieties [19,80,87]. ...
Mangrove swamp rice production (MSRP) refers to rice cultivation in former mangrove soils that have been anthropogenically modified for food production. The method utilizes the largest possible storage of fresh water to desalinate the soils and make them productive. However, temporal variability in rainfall patterns causes loss of efficiency in production, impacting crop growth and reducing productivity. To improve MSRP, it is necessary to identify the primary constraints associated with salinity, enhancing and maximizing freshwater storage efficiency and water productivity. This study provides a general description of the MSRP system in both the northern and southern regions of Guinea-Bissau, aiming at the identification of the main water management limitations. The description involves the use of typologies and the identification of zones with specific characteristics within the paddies. Furthermore, this review includes an analysis of the physicochemical characteristics of soils in relation to salinity issues, descriptions of agronomic management, rice varieties, and the significance of managing dikes and bunds to improve mangrove swamp rice water management. This study shows how the MSRPS is characterized by dynamism and complexity, involving a wide range of constraints associated with salinity features, cultural influences, and microclimatic conditions that are subject to temporal variations.
... 6 Both species are grown in Africa, and varieties of O. sativa were brought to West Africa as a result of trade between Africa and India. 7 O. glaberrima's yield is thought to be lower than O. sativa's, probably as a result of many features such as lodging and grain breaking, 8 and as a result, O. sativa has continued to take over its growing regions. 8 O. glaberrima, however, is still grown in Africa today 9 and is preferred by local farmers over O. sativa for some reasons, including resilience to a variety of regional restrictions, taste, hardiness, and resistance to many biotic and abiotic stresses. ...
... 7 O. glaberrima's yield is thought to be lower than O. sativa's, probably as a result of many features such as lodging and grain breaking, 8 and as a result, O. sativa has continued to take over its growing regions. 8 O. glaberrima, however, is still grown in Africa today 9 and is preferred by local farmers over O. sativa for some reasons, including resilience to a variety of regional restrictions, taste, hardiness, and resistance to many biotic and abiotic stresses. 10 It's been reported that farmers abandoned better O. sativa cultivars to resume the cultivation of O. glaberrima. ...
... Alternatively, O. glaberrima's unfavorable traits may have led to its use primarily as a genetic resource to enhance O. sativa. 8 This shouldn't be a problem today, though, as recent developments in genome editing technologies, like the CRISPR/Cas 9 system, 52-54 may make it possible to eliminate undesirable traits in O. glaberrima and even hasten the process of domestication. 55 The best way to improve O. glaberrima, for instance, maybe to use CRISPR/Cas9 technology to edit and modify the genes responsible for traits like grain shattering and lodging resistance. ...
Africa has the world’s fastest rate of population expansion, making it vulnerable to food shortages. Africa cultivates two types of rice (Asian rice; Oryza sativa and African rice; Oryza glaberrima). Native African rice called O. glaberrima has some intriguing characteristics, including resistance to several biotic and abiotic regional restrictions in Africa. However, O. glaberrima is solely employed as a tool to increase the production of O. sativa, which cannot grow in Africa, due to its low yield, lodging, grain breaking, and poor tissue culture ability. Enhancing breeding efforts for O. glaberrima is therefore critically important. The protocols for transformation and regeneration, however, are mostly for O. sativa and not O. glaberrima. This study examines the present problems with transformation and regeneration for African rice species as well as potential solutions for using modern breeding methods in O. glaberrima.
... Wang et al., 2014). Curiously, the floral integrator Ehd1 was originally identified in a study that mapped a QTL controlling Hd by using a population obtained crossing an accession of O. glaberrima with the T65 variety of O. sativa: Ehd1-gla appeared to be dominant over Ehd1-osa, thus conferring anticipated flowering (Doi et al., 1998) (Linares, 2002). In addition, several accessions have acquired tolerance to a broad range of abiotic stresses (Wambugu et al., 2021). ...
... Indeed, these genetic resources can be exploited to transfer adaptive traits (controlled by gene pools for tolerance to diverse abiotic stresses) to elite varieties. However, African rice also shows undesirable characteristics such as small and brittle grains that are difficult to mill, and low yield (Linares, 2002). ...
... In the 1990s, pioneering breeding programmes employed crosses between the two species (glaberrima and sativa) of the same genus (Oryza) to combine stress tolerance of African rice with the productivity of the Asian rice, and to generate novel varieties with enhanced adaptability to environmental fluctuations and increased grain yield. Yet, the feasibility of this approach was hampered by reproductive barriers between Asian and African rice species (Linares, 2002), mainly caused by the male and female components of the S1 locus [discussed in (Garavito et al., 2010)]. ...
The evolutionary paths of humans and plants have crossed more than once throughout millennia. While agriculture contributed to the evolution of societies in prehistory, human selection of desirable traits contributed to the evolution of crops during centuries of cultivation. Among cereal crops, rice is currently grown around the globe and represents staple food for almost half of the world population. Over time, rice cultivation has expanded from sub‐tropical to temperate regions thanks to artificial selection of mutants with impaired response to photoperiod. Additional regulatory mechanisms control flowering in response to diverse environmental cues, anticipating or delaying the floral transition to produce seeds in more favorable conditions. Nevertheless, the changing climate is threatening grain production because modern cultivars are sensitive to external fluctuations that go beyond their physiological range. One possibility to guarantee food production could be the exploitation of novel varieties obtained by crossing highly productive Asian rice with stress tolerant African rice. This review explores the genetic basis of the key traits that marked the long journey of rice cultivation from the end of the Paleolithic to the Anthropocene, with a focus on heading date. By 2050, will rice plants of the future flower in the outer space? This article is protected by copyright. All rights reserved.
... Early Portuguese colonialists to the Upper Guinea Coast in the 16th century, for example, observed a rather sophisticated indigenous rice production system, including the construction of dikes to retain swampy conditions, and transplanting of the sprouted crop on less swampy grounds. The fact that the Jola people of Senegal's Casamance region and in Guinea-Bissau and Guinea Conakry used similar techniques to grow rice as recently as the 1960s (Linares, 2002) is testament to the enduring strength of cultural heritage across generations in these areas. From these discussions, it can be understood that diverse aspects of food production and consumption identities have been, and are shaped by cultural heritage. ...
... The African Oryza glaberrima species is believed to have been domesticated about 2000-3000 years ago in the Middle Niger Delta in present-day Mali, from where it spread to two secondary centers of domestication. As mentioned earlier, Oryza glaberrima was recorded by early Portuguese colonialists in the region around the 15th and 16th centuries to still be in cultivation by locals along the coast of West Africa (Linares, 2002), described as "the West African rice belt" by Richards (1985), having transcended multiple generations over centuries. ...
... Although O. glaberrima has been gradually substituted with the higher yielding Asian variety, O. sativa, Linares (2002) reported scattered cultivations of the former in a few West African regions, suggestive of strong cultural ties to ancestors. In addition to cultural heritage, other salient factors have been recognized as contributing to the enduring cultivation of the O. glaberrima species across several centuries. ...
Though enormous strides have been achieved in recent decades towards reducing food insecurity in the Global South, continued efforts are imperative in light of rapidly expanding populations and threats posed by climate change. A relatively unexplored area in this arena is the nexus between cultural heritage and food security. Cultural heritage embodies indigenous culture, values, and traditions inherited from previous generations. We focus on rice and identify five pathways through which cultural heritage affects food security. Although policy makers face the complex task of balancing trade-offs between preserving cultural heritage and productivity, they can harness cultural heritage to enhance food security by supporting (i) preservation of genetic resources, (ii) valorization, (iii) traditional food processing, (iv) preference matching, and (v) agritourism.
... Genotypes of 0. glaberrima (AA genome, 2n = 24) are inherently cultivated rice species of Africa origin with two major a300 ecotypes which include 1: floating photosensitive ecotype grown in deep water and coastal mangrove areas of sub Saharan Africa, and 2: early erect ecotype grown in upland or in moderately inundated lowland conditions (Sarla and Swamy, 2005;Besancon et.al., 1984). The genotype of Asian rice species (0. saliva) belong to the same genome group (AA genome, 2n = 24) but spread widely around the world and more diverse and widely cultivated than 0. glaberrima and lower yielding than those of 0. saliva and are therefore cultivated in fewer areas (Linares, 2002). It is well known that Oriza glaberrima can grow and tolerate harsh African environment with multiple stress. ...
... In addition to its ability to withstand drought, it has the capability to recover very fast on receipt of moisture. Although, 0. glaberrima are inherently lower yielding than those of 0. saliva and are therefore cultivated in fewer areas (Linares, 2002). It is well known that Oryza glaberrima grow favorably under varied conditions and can tolerate harsh African environment even under severe stress. ...
... It would have been unlikely that the Southern Africa group individuals hybridized with both O. sativa and O. glaberrima, given that O. glaberrima is primarily cultivated in Northwestern Africa and that O. barthii is sympatric with all of the O. longistaminata groups identified (Vaughan, 1994) Bolstering the interspecific hybridization hypothesis is the observation that the current pattern of low-level O. sativa admixture in O. longistaminata (ubiquitous in the Southern Africa group but rare in the Northwestern Africa and Pan-Africa groups) mirrors the historical timing and location of Asian domesticated rice cultivation in Africa. Intriguingly, recent archaeological and molecular genetic data indicate that O. sativa was introduced to southeastern Africa via Madagascar and the Comoros Islands by farmers who migrated from Southeast Asia across the Indian Ocean as early as~1,000 years before present (Mather et al., 2010;Crowther et al., 2016), which could account for (Linares, 2002). Though Asian domesticated rice, O. sativa, was likely introduced into West Africa by Europeans as early as the mid-16th century, extensive production of Asian rice in West Africa and its replacement of African rice cultivars primarily occurred recently, in the second half of the 20th century (Linares, 2002). ...
... Intriguingly, recent archaeological and molecular genetic data indicate that O. sativa was introduced to southeastern Africa via Madagascar and the Comoros Islands by farmers who migrated from Southeast Asia across the Indian Ocean as early as~1,000 years before present (Mather et al., 2010;Crowther et al., 2016), which could account for (Linares, 2002). Though Asian domesticated rice, O. sativa, was likely introduced into West Africa by Europeans as early as the mid-16th century, extensive production of Asian rice in West Africa and its replacement of African rice cultivars primarily occurred recently, in the second half of the 20th century (Linares, 2002). Thus, opportunities for hybridization between O. sativa and O. longistaminata in West Africa were likely infrequent until modern times. ...
The undomesticated rice relative Oryza longistaminata is a valuable genetic resource for the improvement of the domesticated Asian rice, Oryza sativa . To facilitate the conservation, management, and use of O. longistaminata germplasm, we sought to quantify the population structure and diversity of this species across its geographic range, which includes most of sub-Saharan Africa, and to determine phylogenetic relationships to other AA-genome species of rice present in Africa, including the prevalence of interspecific hybridization between O. longistaminata and O. sativa . Though past plant breeding efforts to introgress genes from O. longistaminata have improved biotic stress resistance, ratooning ability, and yield in O. sativa , progress has been limited by substantial breeding barriers. Nevertheless, despite the strong breeding barriers observed by plant breeders who have attempted this interspecific cross, there have been multiple reports of spontaneous hybrids of O. sativa and O. longistaminata (aka “Obake”) obtained from natural populations in Africa. However, the frequency and extent of such natural introgressions and their effect on the evolution of O. longistaminata had not been previously investigated. We studied 190 O. longistaminata accessions, primarily from the International Rice Research Institute genebank collection, along with 309 O. sativa , 25 Oryza barthii , and 83 Oryza glaberrima control outgroups, and 17 control interspecific O. sativa / O. longistaminata hybrids. We analyzed the materials using 178,651 single-nucleotide polymorphisms (SNPs) and seven plastid microsatellite markers. This study identified three genetic subpopulations of O. longistaminata , which correspond geographically to Northwestern Africa, Pan-Africa, and Southern Africa. We confirmed that O. longistaminata is, perhaps counterintuitively, more closely related to the Asian species, O. sativa , than the African species O. barthii and O. glaberrima . We identified 19 recent spontaneous interspecific hybrid individuals between O. sativa and O. longistaminata in the germplasm sampled. Notably, the recent introgression between O. sativa and O. longistaminata has been bidirectional. Moreover, low levels of O. sativa alleles admixed in many predominantly O. longistaminata accessions suggest that introgression also occurred in the distant past, but only in Southern Africa.
... TT3 is a QTL contributing to rice thermotolerance, and the TT3 CG14 allele from African rice results in a heat-tolerant phenotype . Interestingly, the three QTLs TT1, TT2, and TT3 of African rice demonstrate good breeding potential, consistent with the distribution of African rice in tropical regions and the evolution of delicate mechanisms for adapting to high temperatures (Linares, 2002;Sakai et al, 2011). Therefore, it is crucial to further investigate heat-tolerance QTLs in African rice for heat-tolerance breeding. ...
... This highlights the importance of selecting suitable materials for mining and utilizing heat-tolerant gene resources. African rice possesses subtle mechanisms that enable it to adapt to high temperatures, making it a valuable genetic resource for rice thermotolerance breeding (Linares, 2002;Sakai et al, 2011). Additionally, wild rice is known to contain more abundant gene resources than cultivated rice (Reuscher et al, 2018;Yuan et al, 2022). ...
Global warming poses a threat to rice production. Breeding heat-tolerant rice is an effective and economical approach to addressing this challenge. African rice is a valuable genetic resource for developing heat-tolerant crops due to its intricate mechanism for adapting to high temperatures. Oryza longistaminata, a wild rice species widely distributed in Africa, may harbor an even richer gene pool for heat tolerance, which remains untapped. In this study, we identified three heat-tolerant QTLs from O.longistaminata at the seedling stage. Among these, qTT4 and qTT5 are novel heat-tolerant loci identified in O. longistaminata. Our findings demonstrated that the O. longistaminata alleles for these two QTLs can enhance the heat tolerance of rice seedlings. Remarkably, qTT5 was mapped to a region spanning approximately 287.2 kb, containing 46 expressing genes. Through the analysis of Gene Ontology and expression differences under heat induction, we identified four candidate genes. Our results lay the foundation for the discovery of heat-tolerant genes underlying O. longistaminata and the development of new genetic resources for heat tolerant rice breeding.
Key words: wild rice; Oryza longistaminata; heat tolerance; QTL
... Besides the well-known Asian rice species Oryza sativa L., the African rice species Oryza glaberrima Steud. is the second cultivated rice species. While Oryza sativa is cultivated in most continents, Oryza glaberrima is only cultivated in Africa (Linares, 2002). This marginal species is considered as able to tolerate various biotic and abiotic stresses Wambugu et al., 2019), but its capacity to cope with salinity remains poorly documented. ...
... This confirmed the report of Prodjinoto et al. (2018) who demonstrated that TOG5307 and TOG5949 displayed contrasting levels of salt-resistance at the seedling stage. Compared to Asian rice species Oryza sativa, the African rice species Oryza glaberrima is considered as low yielding due to lodging, grain shattering, and low spikelet number (Linares, 2002;Montcho et al., 2013). In this study, we recorded that both studied cultivars produced at least 50% of filled grains during salt stress, but that an obvious decrease in spikelet fertility was recorded at the basal part of the panicle in the salt-sensitive TOG5949. ...
Salinity is one of the major environmental stresses limiting growth and yield of rice. The objective of the present study was to analyze the impact of NaCl on yield-related parameters of Oryza glaberrima . Two contrasted cultivars of Oryza glaberrima previously tested for salt resistance at the vegetative stage [salt-resistant (TOG5307) and salt-sensitive (TOG5949)] were irrigated with a saline solution containing 30 mM NaCl (EC: 3 dS.m ⁻¹ NaCl). After 6 months of treatments, mineral nutrient and yield-related parameters were assessed. Proline was quantified in the panicle leaf at the start of the grain filling stage. NaCl treatment affected most yield-related parameters: panicle length, panicle leaf dry weight, number of branches per panicle, panicle leaf length, days to 50% heading, straw fresh weight per plant, grain yield per plant, number of spikelets per panicle, and number of filled grains per panicle. The weight of 1,000 grains decreased in the salt-sensitive cultivar only, suggesting that grain filling processes were compromised. The salt-resistant cultivar TOG5307 was less affected than the salt-sensitive TOG5949 and accumulated lower amounts of Na ⁺ in the grains. For both cultivars, hulls contained higher concentration of Na ⁺ and K ⁺ than grains. TOG5307 also contained more proline in the panicle leaf than TOG5949, suggesting that TOG5307 can cope with the osmotic component of salt stress. The cultivar exhibiting the highest salt resistance at the vegetative stage also exhibited the highest resistance at the reproductive one.
... Asian cultivated rice (Oryza sativa L.) was domesticated from the Asian wild rice species, Oryza rufipogon around 8,000 to 10,000 y ago (5). African cultivated rice (Oryza glaberrima Steud.) was thought to have been domesticated from the African wild rice species, Oryza barthii, around 3,000 y ago based on archeological evidence (6,7). However, recent genome-wide analysis suggests that O. glaberrima experienced a prolonged contraction of effective population size (N e ) beginning as early as 15,000 y ago; this was hypothesized to have resulted from a combination of climatic factors (8) and possibly early low-intensity cultivation (9) (SI Appendix, Fig. S1A). ...
... Domestication. To test for a selective sweep in the region of Ograe3, we further examined resequencing data from diverse accessions of O. glaberrima (n = 120) and O. barthii (n = 62), originating from several locations, including around the Niger River where African rice domestication occurred (6,19,20) (SI Appendix, Fig. S10A and Table S2). Nucleotide diversity (π) of O. glaberrima was estimated relative to that of O. barthii in 10-kb window bins across chromosome 6 (Fig. 4A). ...
Two species of rice have been independently domesticated from different ancestral wild species in Asia and Africa. Comparison of mutations that underlie phenotypic and physiological alterations associated with domestication traits in these species gives insights into the domestication history of rice in both regions. Asian cultivated rice, Oryza sativa, and African cultivated rice, Oryza glaberrima, have been modified and improved for common traits beneficial for humans, including erect plant architecture, nonshattering seeds, nonpigmented pericarp, and lack of awns. Independent mutations in orthologous genes associated with these traits have been documented in the two cultivated species. Contrary to this prevailing model, selection for awnlessness targeted different genes in O. sativa and O. glaberrima. We identify Regulator of Awn Elongation 3 (RAE3) a gene that encodes an E3 ubiquitin ligase and is responsible for the awnless phenotype only in O. glaberrima. A 48-bp deletion may disrupt the substrate recognition domain in RAE3 and diminish awn elongation. Sequencing analysis demonstrated low nucleotide diversity in a ~600-kb region around the derived rae3 allele on chromosome 6 in O. glaberrima compared with its wild progenitor. Identification of RAE3 sheds light on the molecular mechanism underlying awn development and provides an example of how selection on different genes can confer the same domestication phenotype in Asian and African rice.
... Integrating staple foods, increasing staple food health qualities, and reducing obstacles to eating healthier foods all contribute to better nutrition and food security (Dixon et al., 2020). The two rice species commonly cultivated globally are (African Oryza glaberrima and Asian Oryza sativa) (Linares, 2002). They are physically similar but ecologically distinct. ...
... They are physically similar but ecologically distinct. Compared to the Asian O. sativa, O. glaberrima is more resistant to illnesses and pests (Linares, 2002). Furthermore, O. glaberrima is less prone to weeds due to its broader leaves, which shade weeds. ...
Rice (Oryza sativa) is among Nigeria's top priority staple crops that play a role in food security and livelihood resilience within the household. Different varieties of rice landraces are grown in Nigeria; Abakaliki rice is grown in Ebonyi State and consumed in almost all parts of the country. This study evaluated the fatty acid composition of parboiled and un-parboiled Abakaliki rice landraces. The GC-MS analysis revealed that myristic, myristoleic, oleic, linoleic and vaccenic fatty acids were the most dominant in the rice landraces. In addition, all study samples contain a total amount of vaccenic (34.45%), oleic (33.36%) and myristic (21.68%) fatty acid, however myristoleic (3.3%) and linoleic (7.5%) fatty acid is in low amount. This study reveals that these fatty acids are 63.82% higher in the parboiled rice cultivars than in the un-parboiled rice.
... Rice (Paddy) is an important staple and primary food crop grown worldwide (Linares, 2002). The morphological and molecular characterization of O. glaberrima assures the existence of a relatively high reservoir of genetic diversity in the area. ...
Plant development has been positively associated with microorganisms
exhibited on the surface (epiphytic), inside (endophytic) and close to the root
(rhizosphere). The plant organs such as the leaf, stem, and root tissues are
internally colonized by diverse and ubiquitous microorganisms comprising
bacterial, fungal, archeal, and protist communities. These inside living
microbes exhibited an endophytic microbiome and play a vital role in seed
germination, growth, development, fitness, abiotic, pathogen protection, and
diversification. The plant endomicrobiome dynamics offer mutualism to
pathogenicity services for plant development. Endomicrobiome offers plant
health beneficial activities such as nutrient availability, phytohormones,
stress regulators, metabolites, osmoprotectants, volatile organic carbons,
antibiotics, and unknown substances for growth promotion. Endophytes
colonize inner host tissues, sometimes in high numbers, without a negative
effect on the host and eliciting a strong defense response. The unexpected change in a global environment, land use change, agrochemicals input,
urbanization, and industrialization effectively decline crop productivity, lead
to an unfertile agriculture ecosystem and affect agriculture sustainability.
Poor soil health, stagnant standing crops and progressive environmental
perturbations possess the problem of food insecurity. Cereal crops such as
maize, rice, and wheat feed a large count of global population and ensure food
and nutritional security. In this chapter, we discuss plant endomicrobiome
diversity, mechanisms, services in cereal crop promotion and stress toxicity
management. However, in addition, the plant endomicrobiome association
offers nature-based solutions (NbS) for agricultural sustainability and next generation global food security.
... The first colonial and trade expeditions, dating from the 15th century, had a big influence on West African crop diversity through the introduction and diffusion of new crop species and varieties (Alpern, 1992(Alpern, , 2008. Peanut (Bernards, 2019), Asian rice (Linares, 2002), maize (McCann, 2005), and manioc (Carter et al., 1994) were introduced in West Africa in the sixteenth century by Portuguese traders. ...
... With changing rainfall patterns and a short rainy season window, farmers need to adapt and start tilling on plots that require less rainfall or soil moisture, such as plots with a loam or sand texture [78]. In this way, they can use these plots to plant nurseries and initiate the rice growth cycle since the species Oryza glaberrima and O. sativa require approximately 90 to 135 days from sowing to harvest [9,17,[79][80][81]. This paper proposes an adaptation strategy that allows farmers to identify the sites where it is appropriate to initiate soil tillage ( Figure 10). ...
The mangrove swamp rice production system (MSRPS) in West Africa faces significant
challenges in soil, water, and salinity management, making rice production highly vulnerable to
variations in the spatio-temporal distribution patterns of rainfall, which are exacerbated by climate
change. This study’s results can provide the initial basis for co-developing strategies with farmers
aiming to contribute to the biophysical characterization of the MSRPS, in particular: (i) estimate
the water-harvesting efficiency (WLef) of the plots in the north and south of Guinea Bissau (GB);
(ii) characterize the unevenness of the bottom of the plots, which leads to salinization spots; and
(iii) create soil consistency maps to provide farmers with a tool to prioritize sites with optimal
conditions for tillage. The research was conducted between 2021 and 2023 in the study site of
Cafine-Cafal in the south and Elalab in the north of GB. Systematic soil sampling in a grid was
designed to quantify the soil consistency and plot/ridge areas were determined. Linear models were
developed to predict biophysical parameters (e.g., effective planting areas and water-logging depths)
and geostatistics were used to create soil consistency maps for each study site. The results show
precipitation water-harvesting efficiencies of 15% and 16% for the southern and northern regions,
respectively. Furthermore, the plasticity limits of 18.6% for Elalab and 35.5% for Cafine-Cafal show
the most appropriate times to start tillage in specific areas of the paddies. This study provides
information on the efficient management of tillage and freshwater conservation, providing MSRPS
farmers with useful tools to counteract the effects caused by salinity and rainfall variability.
... Similar results were reported earlier by Veni and Rani [17]; Das and Ghosh [18], and others have also reported findings that are comparable, Patel et al. [19]; Acharya et al. [20]; Lakshmi et al. [13]; Sreelakshmi and Babu [21]; Kumar et al. [16], as well as Manivelan et al. [14] in their respective studies. [16], as well as Manivelan et al. [14] in their respective studies in their respective studies [23]. ...
Fourteen diverse cultivars of paddy grown in a Randomized Block Design (RBD) at AKS University, Satna, during Kharif season on July 2022. Data were collected foreleven quantitative traits and estimated forvariance,genetic variability, heritability and genetic advance.The design of the experiment indicated highly significant differences for all the characters due to treatments. The analysis of variance indicated the existence of sufficient amount of variability among genotypes for all the studiedcharacters. The maximum GCV along with PCV was observed forgrain yield per plant (g) followed by panicle length (cm), number of spikelets per panicle, harvest index (%), kernel length (mm), number of panicles per plant. Higher estimates (h2b) >80% were observed for Number of spikelets per panicle, days to development, plant level (cm), number of panicles per plant, test weight (g), grain yield per plant (g), panicle length (cm). High heritability combined with high hereditary development for the person number of panicles per plant, number of spikelets per panicle, panicle length (cm), test weight (g) and grain yield per plant (g) indicating that these characters could be prominently governed by additive gene action.
... In Africa, O. glaberrima, the source of most RYMV resistance genes, has been increasingly replaced by higher yielding O. sativa varieties that do not have the full spectrum of resistance (R) genes in their gene pool (Linares, 2002). Introgression of suitable R genes for RYMV from O. glaberrima into O. sativa remains challenging due to crossing barriers (Garavito et al., 2010). ...
Rice yellow mottle virus (RYMV) causes one of the most devastating rice diseases in Africa. Management of RYMV is challenging. Genetic resistance provides the most effective and environment‐friendly control. The recessive resistance locus rymv2 ( OsCPR5.1 ) had been identified in African rice ( Oryza glaberrima ), however, introgression into Oryza sativa ssp. japonica and indica remains challenging due to crossing barriers. Here, we evaluated whether CRISPR/Cas9 genome editing of the two rice nucleoporin paralogs OsCPR5.1 ( RYMV2 ) and OsCPR5.2 can be used to introduce RYMV resistance into the japonica variety Kitaake. Both paralogs had been shown to complement the defects of the Arabidopsis atcpr5 mutant, indicating partial redundancy. Despite striking sequence and structural similarities between the two paralogs, only o scpr5.1 loss‐of‐function mutants were fully resistant, while loss‐of‐function oscpr5.2 mutants remained susceptible, intimating that OsCPR5.1 plays a specific role in RYMV susceptibility. Notably, edited lines with short in‐frame deletions or replacements in the N‐terminal domain (predicted to be unstructured) of OsCPR5.1 were hypersusceptible to RYMV. In contrast to mutations in the single Arabidopsis AtCPR5 gene, which caused severely dwarfed plants, oscpr5.1 and oscpr5.2 single and double knockout mutants showed neither substantial growth defects nor symptoms indicative lesion mimic phenotypes, possibly reflecting functional differentiation. The specific editing of OsCPR5.1 , while maintaining OsCPR5.2 activity, provides a promising strategy for generating RYMV‐resistance in elite Oryza sativa lines as well as for effective stacking with other RYMV resistance genes or other traits.
... The first colonial and trade expeditions, dating from the 15th century, had a big influence on West African crop diversity through the introduction and diffusion of new crop species and varieties (Alpern, 1992(Alpern, , 2008. Peanut (Bernards, 2019), Asian rice (Linares, 2002), maize (McCann, 2005), and manioc (Carter et al., 1994) were introduced in West Africa in the sixteenth century by Portuguese traders. ...
In south-eastern Senegal, Bassari farmers have historically cultivated and consumed a wide diversity of varieties of sorghum, fonio, and Bambara groundnut, most of which thrive in poor soils, are nutritious, and withstand drought. These crops are now on the verge of disappearance from the fields of the Bassari despite their potential fit in the predicted drier climate in the area. To understand why, we explore the intertwining between the local dynamics of crop diversity and socio-economic changes at local, national, and regional scales. We draw upon the critical reading of secondary sources and field data, analyzed through the lens of political agroecology. The abandonment of traditional Bassari crops can be explained by government and international policies that interact with cultural trends and household-level factors. Colonial and post-colonial agricultural policies and research priorities have promoted the expansion of exotic crops with market value or high yield potential (e.g., peanut, cotton, rice, horticultural crops), failing to value indigenous crop diversity. These policies, together with market forces and historical legacies, have intersected with outmigration, dietary changes, decreases in community social capital, and gender-dynamics, favouring the switch from drought-tolerant traditional crops to more water-demanding exotic crops. We then consider what the interplay between social dynamics and crop diversity means under climate change. Our results suggest that current trends in crop diversity might threaten climate resilience in the long-term. Drawing on political agroecology, we discuss potential avenues to support the capacity of Bassari farmers to practice agriculture in a drier climate. We argue that in order to increase the climate resilience of smallholder farmers it is necessary not only to consider the cross-scale processes and multiple dimensions of power that affect crop diversity but also to reconsider research and policy priorities in favour of drought-tolerant indigenous crops.
... From the 15th century onwards, Portugal's early opening up to the world economy exposed it to the intercontinental circulation of different crops, changing the previous geographies of production and consumption within the so-called Columbian Exchange (Crosby, 1972;Carney, 2001;Coclanis, 2011). Although Portugal was one of the first to promote globalisation (Carney, 2001;Ferrão, 2016;Linares, 2002), it was also one of the last European countries where agriculture remained the main social and economic activity, into the 1960s (Amaral & Freire, 2017: 256). Given that the structural changes associated with modern economic growth occurred after the Second World War (Lains, 2003: 369-386), discussing the Portuguese paths to agricultural innovation contributes to a better understanding of the conditions of development on the European periphery, which is the subject of an ongoing debate (North, 1990;Lains, 2017). ...
From its origins in Asia,cultivation of Oryza sativa L. in Portugal has had to adapt to local agroecological conditions.Since the late eighteenth century,there has been significant human intervention in rice production, particularly through public policies aimed at increasing production to achieve national food self-sufficiency. Using national and regional statistics on rice production,this article analyses how public policies on rice cultivation over the last 160 years have impacted and interacted with territorial agroecological conditions and the genetic characteristics of the rice varieties being cultivated.We concluded that public policies led to increased production by favouring the geographical reorganisation of rice production based on the rice varieties used and changing territorial agroecological conditions.
... A major portion of these lands are affected by drought and/or by salinity so that the improvement of salinity resistance in this species appears as a priority [24,25] Beside the cultivated rice species Oryza sativa L, wild relative may provide useful genes to improve salinity resistance but interspecific crosses and cultivar selection is a long-term task and require a big deal of work [23,26,27]. Oryza glaberrima Steud. is an African rice species which is marginally cultivated in Africa but exhibits interesting abilities to cope with environmental constraints [28,29]. Although some informations are currently available for its adaptation to soil drying [30,31] or to iron toxicity [32,33], its level of resistance to salinity remains poorly documented and requires additional investigations. ...
We analyzed the expression of genes coding for Na ⁺ transporters ( OsHKT1 . 5 , OsHKT1 . 1 , OsSOS1 , OsSOS2 , OsNHX1 , OsNHX2 ), Cl ⁻ transporter ( OsNRT1 , OsCLC , OsCCC1 ) and gene coding for the transcription factor DREB ( OsDREB2 ) involved in response to desiccation in two cultivars of O . glaberrrima differing in salt-resistance (salt-tolerant cultivar (TOG5307) and salt-sensitive (TOG 5949)) exposed to NaCl, PEG or both agents present simultaneously. Seedlings were grown in iso-osmotic nutrient solution ( Ψ s = -0.47±0.02 MPa) containing PEG 6,000 12.9% (water stress), NaCl 75 mM (salt stress) and PEG 6.4% + NaCl 37.5 mM (MIX-treatment) during 1 and 7 days. Plants were analyzed for gene expression, mineral nutrients, and photosynthetic-related parameters. Na ⁺ and Cl ⁻ accumulations in salt-treated plants were lower in roots and shoots of TOG5307 comparatively to TOG5949 while water content decreased in TOG5307. TOG5307 exhibited tolerance to water stress and maintained higher net photosynthesis and water use efficiency than TOG5949 in response to all treatments, but was less efficient for osmotic adjustment. Dehydration tolerance of TOG5307 involves a higher OsDREB2 expression. TOG5307 also exhibited a higher OsSOS1 , OsSOS2 , OsNHX1 and OsNHX2 expression than TOG5949 in response to salinity. OsHKT1 . 5 was slightly induced in the shoot. OsHKT1 . 1 was recorded in the shoots but remained undetectable in the roots. Chloride and sodium accumulations were strongly reduced in the shoots when PEG was present. Salinity resistance in Oryza glaberrima implies tolerance to dehydration as well as complementary strategies of Na ⁺ exclusion through the SOS system and Na ⁺ tolerance through vacuolar sequestration.
... We aimed to compare the tolerance to elevated temperatures and longevity in the storage of primed seeds of Oryza sativa, Oryza glaberrima, and interspecific hybrid rice types, and assess their performance after storage stress. O. glaberrima is native to sub-Saharan Africa, while O. sativa was first domesticated in Asia (Linares, 2002). O. glaberrima possesses important adaptive mechanisms and traits, such as drought tolerance, and although it yields less than O. sativa, it remains valuable due to its tolerance to abiotic stresses (Jones et al., 1997;Sarla and Swamy, 2005 ...
• Controlled deterioration of primed seeds led to a substantial reduction in longevity. priming process also makes the seeds more sensitive to storage conditions, resulting in a rapid loss of viability and increased solute leakage.
• Variety CG14, an O. glaberrima variety, maintained its longevity despite elevated Electrical Conductivity and MDA levels, suggesting remarkable tolerance to heat stress. This study underscores the significance of genotype differences in preserving seed longevity, even in primed seeds.
... Cultivation of O. sativa was introduced into West Africa around 400 years ago and this crop has since largely replaced O. glaberrima -although the latter is still grown, it represents only 1-2% of the total cultivated area. O. glaberrima is more adapted to a variety of ecologically and climatically diverse regions, its agronomically useful characters including higher tolerance to drought, high temperatures and infertile soils as well as a greater resistance to various biotic stresses [28][29][30][31][32][33]. While O. sativa is less adapted to the African environment, this species has a higher yield potential than O. glaberrima, the difference being partly explained by the higher panicle complexity of Asian rice [34]. ...
Background
Developing high yielding varieties is a major challenge for breeders tackling the challenges of climate change in agriculture. The panicle (inflorescence) architecture of rice is one of the key components of yield potential and displays high inter- and intra-specific variability. The genus Oryza features two different crop species: Asian rice (Oryza sativa L.) and the African rice (O. glaberrima Steud.). One of the main morphological differences between the two independently domesticated species is the structure (or complexity) of the panicle, with O. sativa displaying a highly branched panicle, which in turn produces a larger number of grains than that of O. glaberrima. The gene regulatory network that governs intra- and interspecific panicle diversity is still under-studied.
Results
To identify genetic factors linked to panicle architecture diversity in the two species, we used a set of 60 Chromosome Segment Substitution Lines (CSSLs) issued from third generation backcross (BC3DH) and carrying genomic segments from O. glaberrima cv. MG12 in the genetic background of O. sativa Tropical Japonica cv. Caiapó. Phenotypic data were collected for rachis and primary branch length, primary, secondary and tertiary branch number and spikelet number. A total of 15 QTLs were localized on chromosomes 1, 2, 3, 7, 11 and 12, QTLs associated with enhanced secondary and tertiary branch numbers were detected in two CSSLs. Furthermore, BC4F3:5 lines carrying different combinations of substituted segments were produced to decipher the effects of the identified QTL regions on variations in panicle architecture. A detailed analysis of phenotypes versus genotypes was carried out between the two parental genomes within these regions in order to understand how O. glaberrima introgression events may lead to alterations in panicle traits.
Conclusion
Our analysis led to the detection of genomic variations between O. sativa cv. Caiapó and O. glaberrima cv. MG12 in regions associated with enhanced panicle traits in specific CSSLs. These regions contain a number of key genes that regulate panicle development in O. sativa and their interspecific genomic variations may explain the phenotypic effects observed.
... In Africa, rice is an indigenous crop growing in importance . Cultural heritage of rice in Western Africa was found to originate from the domestication of African rice species in present-day Mali and was believed to have spread to other regions, including certain parts of The Gambia, Senegal, and Guinea Bissau, and to have been passed on through ethnic lineages (Britwum & Demont, 2021a, 2021bLinares, 2002). In Eastern Africa, rice has emerged as an important staple with increased consumption in several countries such as Kenya, Burundi, Mozambique, and Tanzania (GRiSP, 2013). ...
Improvement of crop varieties can be a powerful strategy for addressing food, nutrition, and climate challenges in the Global South if it is guided by market intelligence. We conducted a systematic literature review of stakeholder preference studies that aim at guiding crop improvement in rice, the Global South's most important staple food. We review behavioral indicators such as purchase intention, willingness to pay, acceptance, probability of adoption, and preference. Results from 106 studies reveal important gaps in terms of geographical and stakeholder representation: (1) Southcentral Asia is underrepresented and (2) studies focused either on upstream (farmers) or downstream (consumers) stakeholders along the value chain, while missing out on midstream actors (processors, traders). From the consumer studies, urban consumption zones are adequately represented as sources of end-market opportunities for farmers to tap into demand. Evidence suggests that consumer preferences for intrinsic attributes revolve around eating and cooking quality attributes (i.e., aroma, texture, swelling capacity, taste) and physical traits (i.e., whiteness, size and shape, proportion of broken grains). Evidence from farmer studies reveals that (1) preferences for agronomic attributes dominate and focus on yield, maturity, plant height, lodging tolerance, and tillering ability; (2) yield and early maturity were generally considered priority attributes and were often jointly considered as such; and (3) preferences for abiotic stress tolerance revolve around drought, submergence, and salinity. These insights can help refocus market intelligence research to aid crop improvement in addressing food, nutrition, and climate challenges in the Global South, which may be expanded globally.
... African rice (Oryza glaberrima Steud.) is a short-day cereal crop closely related to Asian rice (Oryza sativa L.) and has been cultivated in west Sub-Saharan Africa for ∼ 3,000 years (Linares 2002;Cubry et al. 2018). Compared with Asian rice, African rice is less grown globally, but it possesses special traits that are valued to improve Asian rice, including strong resistance to diseases, pests, poor and acid soils, and environmental stresses (Wu et al. 2017;Choi et al. 2019). ...
African rice (Oryza glaberrima Steud.), a short-day cereal crop closely related to Asian rice (Oryza sativa L.), has been cultivated in Sub-Saharan Africa for ∼ 3000 years. Although less cultivated globally, it is a valuable genetic resource in creating high-yielding cultivars that are better adapted to diverse biotic and abiotic stresses. While inflorescence architecture, a key trait for rice grain yield improvement, has been extensively studied in Asian rice, the morphological and genetic determinants of this complex trait are less understood in African rice. In this study, using a previously developed association panel of 162 O. glaberrima accessions and new SNP variants characterized through mapping to a new version of the O. glaberrima reference genome, we conducted a genome-wide association study of four major morphological panicle traits. We have found a total of 41 stable genomic regions that are significantly associated with these traits, of which 13 co-localized with previously identified QTLs in O. sativa populations and 28 were unique for this association panel. Additionally, we found a genomic region of interest on chromosome 3 that was associated with the number of spikelets and primary and secondary branches. Within this region was localized the O. sativa ortholog of the PHYTOCHROME B gene (Oglab_006903/OgPHYB). Haplotype analysis revealed the occurrence of natural sequence variants at the OgPHYB locus associated with panicle architecture variation through modulation of the flowering time phenotype, whereas no equivalent alleles were found in O. sativa. The identification in this study of genomic regions specific to O. glaberrima indicates panicle-related intra-specific genetic variation in this species, increasing our understanding of the underlying molecular processes governing panicle architecture. Identified candidate genes and major haplotypes may facilitate the breeding of new African rice cultivars with preferred panicle traits.
... For example, studies have estimated that 20-50% of all farmers who planted NERICA rice in the early 2000s have since discontinued its use, either because the variety did not provide better profitability in years with poor rainfall or because farmers lacked information about the proper cultivation methods needed for high yields (88,89). Considering the potential scalability of the technology, NERICA varieties have shown the most promise in upland ecologies, which comprise a large proportion (>30%) of rice area in Central and West Africa (90), and could reach nearly 1.7 million farmers (91). ...
Food demand is projected to increase significantly over the coming decades. Sustainable intensification (SI) is essential to meet this demand. SI is particularly important in smallholder systems, yet to date it remains unclear what the most promising SI strategies are to increase food production and farmer incomes at scale. We review the literature on SI to identify the most promising strategies, as manifest in replicated findings of favorable causal impacts. Adoption of improved cultivars generated the largest, most consistent, positive yield and economic outcomes. Two agroecological practices, push-pull systems and the System of Rice Intensification, also repeatedly led to large positive impacts. These strategies have considerable potential to scale to reach more than 50% of smallholder farmers who plant staple crops. Significant barriers to adoption remain, however, and identifying ways to overcome barriers to scale these successful strategies will be critical to meeting Sustainable Development Goals 1 and 2 by 2030.
Expected final online publication date for the Annual Review of Environment and Resources, Volume 48 is October 2023. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
... O. nivara in the phylogeny tree of ClpB1 protein was on the same clade as O. sativa japonica Nipponbare (jap) rice and O. sativa indica (Supplementary Fig. S5), indicating that jap and ind rice are related to O. nivara in their origin (Choi et al. 2017). O. barthii is considered the ancestor of O. glaberrima (Linares 2002); (Li and Olsen 2016) and is being used in the upland rice breeding program of the Africa Rice Center and both these rice types were positioned on the same clade. As represented in Supplementary Fig. S7, ClpB1 protein has characteristically distinct domains. ...
Main conclusion
The Hsp101 gene is present across all sequenced rice genomes. However, as against Japonica rice, Hsp101 protein of most indica and aus rice contain insertion of glutamic acid at 907th position.
Abstract
The understanding of the heat stress response of rice plants is important for worldwide food security. We examined the presence/absence variations (PAVs) of heat shock proteins (Hsps)/heat shock transcription factor (Hsf) genes in cultivated rice accessions. While 53 Hsps/Hsfs genes showed variable extent of PAVs, 194 genes were the core genes present in all the rice accessions. ClpB1/Hsp101 gene, which is critically important for thermotolerance in plants, showed 100% distribution across the rice types. Within the ClpB1 gene sequence, 40 variation sites consisting of nucleotide polymorphisms (SNPs) and short insertion/deletions (InDels) were discerned. An InDel in ClpB1 leading to an in-frame insertion of 3 nucleotides (TCC) thereby an additional amino acid (glutamic acid) at 907th amino acid position was noted in most of the indica and aus as against japonica rice types. Three rice types namely Moroberekan (japonica), IR64 (indica) and N22 (aus) were further analyzed to address the question of ClpB1 genomic variations and its protein levels with the heat tolerance phenotype. The growth profiling analysis in the post heat stress (HS) period showed that N22 seedlings were most tolerant, IR64 moderately tolerant and Moroberekan highly sensitive. Importantly, the ClpB1 protein sequences of these three rice types showed distinct differences in terms of SNPs. As the ClpB1 protein levels accumulated post HS were generally higher in Moroberekan than N22 seedlings in our study, it is proposed that some additional gene loci in conjunction with ClpB1 regulate the overall rice heat stress response.
... However, the yield potential of current hybrid rice varieties, which are mainly based on the utilization of intraspecific heterosis (hybrid vigor), has reached a plateau (Ma and Yuan 2015). There are two cultivated rice species, namely African cultivated rice (Oryza glaberrima Steud) and Asian cultivated rice (Oryza sativa L.) (Linares 2002). Asian cultivated rice comprises two subspecies, japonica and indica. ...
Key message
We identified and fine-mapped S58, a selfish genetic locus from Asian rice that confers hybrid male sterility in crosses between Asian and African cultivated rice, and found a natural neutral allele in Asian rice lines that will be useful for overcoming S58-mediated hybrid sterility.
Abstract
Hybrids between Asian cultivated rice (Oryza sativa L.) and African cultivated rice (Oryza glaberrima Steud) display severe hybrid sterility (HS), hindering the utilization of strong heterosis in hybrids between these species. Several African rice selfish loci causing HS in Asian–African cultivated rice hybrids have been identified, but few such Asian rice selfish loci have been found. In this study, we identified an Asian rice selfish locus, S58, which causes hybrid male sterility (HMS) in hybrids between the Asian rice variety 02428 and the African rice line CG14. Genetic analysis confirmed that S58 causes a transmission advantage for the Asian rice S58 allele in the hybrid offspring. Genetic mapping with near-isogenic lines and DNA markers delimited S58 to 186 kb and 131 kb regions of chromosome 1 in 02428 and CG14, respectively, and revealed complex genomic structural variation over these mapped regions. Gene annotation analysis and expression profiling analyses identified eight anther-expressed candidate genes potentially responsible for S58-mediated HMS. Comparative genomic analysis determined that some Asian cultivated rice varieties harbor a 140 kb fragment deletion in this region. Hybrid compatibility analysis showed that this large deletion allele in some Asian cultivated rice varieties can serve as a natural neutral allele, S58-n, that can overcome S58-mediated interspecific HMS. Our study demonstrates that this selfish genetic element from Asian rice is important for HMS between Asian and African cultivated rice, broadening our understanding of interspecific HS. This study also provides an effective strategy for overcoming HS in future interspecific rice breeding.
... Rice is the most widely consumed main and fundamental food on the planet. Oryza sativa (Asian rice) and O. glaberrima (African rice) are the two primary crop species of cultivated rice (Linares 2002). O. sativa is a high-yielding crop widely farmed around the world, but O. glaberrima has a lower grain yield but is more stress tolerant and is only cultivated in Africa. ...
Arbuscular mycorrhizal fungi (AMF) symbiosis, which may be found in
almost all naturalistic habitats, perform activities such as nutrition uptake,
stress modulation, growth stimulation, soil structure, and fertility management.
AMF easily takes up phosphorus (P) from the soil and transports it to
the plants. AMF facilitates host plants to grow vigorously under nutrientdeficient
conditions by mediating a series of complex communication events
between the plant and AMF leading to enhanced uptake of soil nutrients
and activation of transporter genes. The fundamental processes of P uptake
and utilization, as well as P transport, regulators, root architecture, metabolic
adaptations, quantitative trait loci, hormone signaling, and microRNA, have
been studied based on molecular and genetic investigations. The current
review provides a comprehensive overview of AMF and its effects on rice
and other plants at various stages of development, as well as the benefits,
applications of AMF, and its interactions between different plant nutrients. It
is identified that the expression of certain phosphate transporter family
genes and P concentration in plant biomass was significantly increased as a
result of the symbiotic relationship between AMF and plants. So, AMF’s role
as a bio-fertilizer has the potential to enhance the plant’s ability to adapt to
changing conditions. AMF-related products for agriculture, horticulture, and
landscaping have gained in popularity as a result of AMF’s vast potential
applicability. We go through recent innovations, developments, and molecular breakthroughs in these areas, as well as the benefits and limitations
of using AMF in the future for long-term crop productivity.
... Rice is the most widely consumed main and fundamental food on the planet. Oryza sativa (Asian rice) and O. glaberrima (African rice) are the two primary crop species of cultivated rice (Linares 2002). O. sativa is a high-yielding crop widely farmed around the world, but O. glaberrima has a lower grain yield but is more stress tolerant and is only cultivated in Africa. ...
Arbuscular mycorrhizal fungi (AMF) symbiosis, which may be found in almost all naturalistic habitats, perform activities such as nutrition uptake, stress modulation, growth stimulation, soil structure, and fertility management. AMF easily takes up phosphorus (P) from the soil and transports it to the plants. AMF facilitates host plants to grow vigorously under nutrient-deficient conditions by mediating a series of complex communication events between the plant and AMF leading to enhanced uptake of soil nutrients and activation of transporter genes. The fundamental processes of P uptake and utilization, as well as P transport, regulators, root architecture, metabolic adaptations, quantitative trait loci, hormone signaling, and microRNA, have been studied based on molecular and genetic investigations. The current review provides a comprehensive overview of AMF and its effects on rice and others plants at various stages of development, as well as the benefits, applications of AMF, and its interactions between different plant nutrients. It is identified that the expression of certain phosphate transporter family genes and P concentration in plant biomass was significantly increased as a result of the symbiotic relationship between AMF and plants. So, AMF's role as a bio-fertilizer has the potential to enhance the plants ability to adapt to changing conditions. AMF-related products for agriculture, horticulture, and landscaping have gained in popularity as a result of AMF's vast potential applicability. We go through recent innovations, developments and molecular breakthroughs in these areas, as well as the benefits and limitations of using AMF in the future for long-term crop productivity.
... It is important to note that, there is also a significant variation in vWA domain sequence between OsvWA36 and OsvWA37 proteins. One of the interesting observations is that both these genes were (Linares, 2002). ...
Rice blast is a dreadful disease that causes enormous losses in rice production worldwide. To develop blast resistant rice cultivars, it is necessary to identify resistance and defence regulator genes and the underlying mechanism of resistance. A novel von Willebrand factor domain A containing genes OsvWA36 and OsvWA37 in Tetep cultivar of rice regulate response to Magnaporthe oryzae infection and provides significant resistance. Owing to the important role of these genes, their evolutionary relationship has been studied in cultivated and wild species of rice. There is significant diversity in the protein sequence of these genes among the relative wild rice species. The size of OsvWA36 protein varies from 501 aa to 698 aa whereas size of OsvWA37 protein varies from 295 aa to 1004 aa. The, OsvWA36 gene is evolutionarily more conserved than OsvWA37 among the different rice species indicating its critical role. Besides the global variation in protein sequence, the region of vWA domain is highly conserved among all the species. Interestingly, both the genes in Oryza barthii are fused to form a single gene encoding a large protein that indicates their origin in other species from a single gene. The good quality tertiary structures of both OsvWA36 and OsvWA37 proteins in cultivated germplasm cv. Tetep were also generated which can be utilized for protein structural and docking studies.
... This implies that most of the Pi genes or their allele versions existed in the tested rice panel. Most of the rice cultivated in SSA was introduced from Asia by Europeans in the 16 th century (Linares 2002). This finding shows that cultivars derived from these ancestral populations originally had effective resistance genes, but these may have been overcome or rendered ineffective due to shifts in the virulence spectrum of the pathogen within the new rice growing ecologies of Africa (McDonald and Linde 2002; Onaga et al. 2020). ...
There is a recent unparalleled increase in demand for rice in sub-Saharan Africa, yet its production is affected by blast disease. Characterization of blast resistance in adapted African rice cultivars can provide important information to guide growers and rice breeders. We used molecular markers for known blast resistance genes ( Pi genes; n = 21) to group African rice genotypes ( n = 240) into similarity clusters. We then used greenhouse-based assays to challenge representative rice genotypes ( n = 56) with African isolates ( n = 8) of Magnaporthe oryzae which varied in virulence and genetic lineage. The markers grouped rice cultivars into five blast resistance clusters (BRC) which differed in foliar disease severity. Using stepwise regression, we found that the Pi genes associated with reduced blast severity were Pi50 and Pi65, whereas Pik-p, Piz-t, and Pik were associated with increased susceptibility. All rice genotypes in the most resistant cluster, BRC 4, possessed Pi50 and Pi65, the only genes that were significantly associated with reduced foliar blast severity. Cultivar IRAT109, which contains Piz-t, was resistant against seven African M. oryzae isolates, whereas ARICA 17 was susceptible to eight isolates. The popular Basmati 217 and Basmati 370 were among the most susceptible genotypes. These findings indicate that most tested genes were not effective against African blast pathogen collections. Pyramiding genes in the Pi2/9 multifamily blast resistance cluster on chromosome 6 and Pi65 on chromosome 11 could confer broad-spectrum resistance capabilities. To gain further insights into genomic regions associated with blast resistance, gene mapping could be conducted with resident blast pathogen collections.
[Formula: see text] Copyright © 2023 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license .
... Traditionally among the Balanta, a man has to produce enough rice to sell and buy (or exchange with) cattle, which would be slaughtered during his and his relatives mourning ceremonies exhibiting his richness and skills as a rice producer (Temudo and Abrantes 2015). The Diola believe it was God who gave them the seedsand indeed they contributed to African rice domestication (Linares 1981(Linares , 2002)and each man creates a stock of rice during his life to be exhibited at his mourning ceremony as a sign of his work ethic. For both groups, rice production using a long-handled wooden plough is an identity marker: they are 'ploughers' (labradures in Creole), even when they are also slash-and-burn farmers (pabidures in Creole). ...
Purpose
To advance understanding about the way endogenous knowledge on mangrove swamp rice (MSR) farming is transmitted, reinvented and negotiated between generations and highlight the implications this has for R4D.
Design/Methodology/Approach
Long-term qualitative research using an ethnographic approach, technography and biographies of farmers.
Findings
The endogenous Agricultural Knowledge and Innovation System (AKIS) is dynamic but faces shortcomings owing to socio-environmental changes. This highlights the relevance of knowledge exchanges from multiple sources, eroding the divide between endogenous and exogenous from the farmers’ point of view. For positive exogenously induced socio-technical change to occur, external actors must fully understand the conditions under which (a) endogenous knowledge is produced and reinvented and (b) endogenous innovations flow among farmers. This will then allow the co-production of innovations adapted to each specific agro-ecological, cultural and socio-economic context, leaving them to be further transformed and refashioned by smallholders to meet their individual ‘dispositions’ and generate the roots necessary for a strong AKIS.
Practical implications
This paper highlights the importance of locally embedded processes of learning and innovation, the better understanding of which can provide a more solid basis for the co-production of technologies and the establishment of an AKIS.
Theoretical implications
This paper improves understanding of socio-technological change in smallholder agriculture by focusing on endogenous processes of learning and innovation.
Originality
This paper advances the knowledge on endogenous processes of learning and socio-technical change in smallholder agriculture.
... In Africa O. glaberrima, which is the source of most RYMV resistance genes, has been increasingly replaced by higher yielding O. sativa varieties that do not have the full spectrum of resistance (R) genes in their gene pool (Linares, 2002). Introgression of suitable R genes for RYMV from O. glaberrima into O. sativa remains challenging due to crossing barriers (Garavito et al., 2010). ...
Rice yellow mottle virus (RYMV) causes one of the most devastating rice diseases in Africa. Management of RYMV is challenging. Genetic resistance provides the most effective and environment-friendly control. The recessive resistance locus rymv2 (OsCPR5.1) had been identified in African rice (O. glaberrima), however, introgression into O. sativa ssp. japonica and indica remains challenging due to crossing barriers. Here, we evaluated whether CRISPR/Cas9 genome editing of the two rice nucleoporin paralogs OsCPR5.1 (RYMV2) and OsCPR5.2 can be used to introduce RYMV resistance into the japonica variety Kitaake. Both paralogs had been shown to complement the defects of the Arabidopsis atcpr5 mutant, indicating partial redundancy. Despite striking sequence and structural similarities between the two paralogs, only oscpr5.1 loss-of-function mutants were fully resistant, while loss-of-function oscpr5.2 mutants remained susceptible, intimating that OsCPR5.1 plays a specific role in RYMV susceptibility. Notably, edited lines with short in-frame deletions or replacements in the N-terminal domain (predicted to be unstructured) of OsCPR5.1 were hypersusceptible to RYMV. In contrast to mutations in the single Arabidopsis AtCPR5 gene, which caused severely dwarfed plants, oscpr5.1 and oscpr5.2 single knockout mutants show neither substantial growth defects nor symptoms indicative of programmed cell death, possibly reflecting functional redundancy of the isoforms regarding other important functions. The specific editing of OsCPR5.1, while maintaining OsCPR5.2 activity, provides a promising strategy for generating RYMV-resistance in elite Oryza sativa lines as well as for effective stacking with other RYMV resistance genes or other traits.
... sativa). However, in marginal areas under poor crop management, O. glaberrima is still favoured by farmers for its tolerance to multiple biotic and abiotic stress such as high temperature, Rice Yellow Mottle Virus (RYMV), drought, flood and weeds (Jones et al., 1997;Li et al., 2015;Linares, 2002;Thiemele et al., 2010;Zhang et al., 2022). ...
African cultivated rice (Oryza glaberrima Steud.) was domesticated from its wild progenitor species (Oryza barthii) about 3,000 years ago. Seed shattering is one of the main constraints on grain production in African cultivated rice, which causes severe grain losses during harvest. By contrast, Asian cultivated rice (Oryza sativa) displays greater resistance to seed shattering, allowing higher grain production. A better understanding in regulation of seed shattering would help to improve harvesting efficiency in African cultivated rice. Here, we report the map‐based cloning and characterization of OgSH11, a MYB transcription factor controlling seed shattering in O. glaberrima. OgSH11 represses the expression of lignin biosynthesis genes and lignin deposition by binding to the promoter of GH2. We successfully developed a new O. glaberrima material showing significantly reduced seed shattering by knockout of SH11 in O. glaberrima using CRISPR‐Cas9 mediated approach. Identification of SH11 not only supplies a new target for seed shattering improvement in African cultivated rice, but also provides new insights into the molecular mechanism of abscission layer development.
... Oyrza barthii (Oryza abreviligulata) is the wild progenitor of cultivated African rice. It is an annual cereal that commonly grows in seasonally flooded areas from Mauritania to Tanzania and from the Sudan to Botswana (Linares, 2002). The nomenclature of wild rice in Africa has been very confused. ...
Wild rice (Oryza barthii) is increasingly used in Sudan as a food crop. Wild rice is a whole grain, rich
in minerals, vitamins, protein, starch, dietary fiber and various phytochemicals; and yet low in fat, with
a beneficial fatty acids profile. The objective of this study was to evaluate the socioeconomic significance
of wild rice as a famine food crop in Darfur state of Sudan. A study was conducted in five districts
(Tullus, Gadad, Demso, Katila, and Umshtoor) in South Darfur in Sudan. Primary data were obtained
through a face-to-face semi-questionnaire interview on 146 households; supplemented with interviews
of key informants and group discussions. All respondents (100%) not only attested to knowing wild
rice and its growth habits, but also consumption (93.8%) of the crop. Wild rice reportedly grows
naturally and widely in valleys, although it was dismally exploited by the local population. It is
harvested manually and traditionally; and sold mostly in the local markets, without post-harvest value
additions. The crop is consumed in various meals, but mainly in the form of porridge. Some respondents
(13%) used the crop in times of famine. Wild rice is stored in traditional containers (95.9%) for periods
ranging from 8 to 12 years without visible storage problems.
... The poor yields of neglected crops are due to the absence of genetic improvement. For instance, the grain yields of neglected crops such as teff, millets, and African rice (Oryza glaberrima) are very low due to lodging, grain shattering, and other constraints (Assefa et al., 2011;Linares, 2002). The use of biotechnology and molecular approaches such as molecular marker characterization of genetic diversity, marker-assisted selection, tissue culture, micropropagation, genomics, and transgenics alongside conventional breeding can help limit undesired traits in NUS ( Fig. 1.2). ...
... Oyrza barthii (Oryza abreviligulata) is the wild progenitor of cultivated African rice. It is an annual cereal that commonly grows in seasonally flooded areas from Mauritania to Tanzania and from the Sudan to Botswana (Linares, 2002). The nomenclature of wild rice in Africa has been very confused. ...
Wild rice (Oryza barthii) is increasingly used in Sudan as a food crop. Wild rice is a whole grain, rich in minerals, vitamins, protein, starch, dietary fiber and various phytochemicals; and yet low in fat, with a beneficial fatty acids profile. The objective of this study was to evaluate the socioeconomic significance of wild rice as a famine food crop in Darfur state of Sudan. A study was conducted in five districts (Tullus, Gadad, Demso, Katila, and Umshtoor) in South Darfur in Sudan. Primary data were obtained through a face-to-face semi-questionnaire interview on 146 households; supplemented with interviews of key informants and group discussions. All respondents (100%) not only attested to knowing wild rice and its growth habits, but also consumption (93.8%) of the crop. Wild rice reportedly grows naturally and widely in valleys, although it was dismally exploited by the local population. It is harvested manually and traditionally; and sold mostly in the local markets, without post-harvest value additions. The crop is consumed in various meals, but mainly in the form of porridge. Some respondents (13%) used the crop in times of famine. Wild rice is stored in traditional containers (95.9%) for periods ranging from 8 to 12 years without visible storage problems.
In this paper we study 500 years of African economic history using traveller accounts. We systematically collected 2464 unique documents, of which 855 pass language and rigorous data quality requirements. Our final corpus of texts contains more than 230 000 pages. Analysing such a corpus is an insurmountable task for traditional historians and would probably take a lifetime's work. Applying modern day computational linguistic techniques such as a structural topic model approach (STM) in combination with domain knowledge of African economic history, we analyse how first‐hand accounts (topics) evolve across space and time. Apart from obvious accounts of climate, geography, and zoology, we find topics around imperialism, diplomacy, conflict, trade/commerce, health/medicine, evangelization, and many more topics of interest to scholarship. We illustrate how this novel database and text analysis can be employed in three applications (1) What views are introduced by travellers as a result of their occupational background? (2) Did the adoption of quinine as treatment and prophylaxis against malaria facilitate European expansion into Africa? (3) When and how did the diffusion of New World crops alter the African economic landscape?
Climate change, ever-increasing global population and declining in the arable land are burning challenges to food and nutritional security. Although over 7000 species are known to have potential for food which are domesticated either partly or fully but very few, about 30 crops, species provide 95% of the world’s food energy. Extensive cultivar improvement and reduced genetic diversity of crops has led them to their vulnerability to various climate change threats. Thus, now strong action is required to emphasize upon the potential of local solutions for sustainable food and agricultural systems and to improve less focused minor crops that conserve a great genetic diversity to use against biotic and abiotic stress management. Large number of orphan crops that can perform better than the staple food crops in less favored circumstances. For example, Niger, a minor oilseed crop can perform better in poorly drained soils. Safflower, another minor oilseed crop can be used for phytoremediation of soils rich in lead, cadmium and zinc as it shows tolerance to heavy metals. Besides this, there exist numerous challenges also for the actual realization of potential of orphan crop plants that needs to be tackled strategically for their promotion, cultivation, consumption, utilization, research and market development. Minor crops hold great opportunity to explore their utilities as feed, fodder, ornamentals, and medicinal properties. Strategic approaches are required to conserve the plant biodiversity of potential crops. Systematic characterization and documentation in gene banks will help the stakeholders to make their optimum utilization.
Food demand is projected to increase significantly over the coming decades. Sustainable intensification (SI) is essential to meet this demand. SI is particularly important in smallholder systems, yet to date it remains unclear what the most promising SI strategies are to increase food production and farmer incomes at scale. We review the literature on SI to identify the most promising strategies, as manifest in replicated findings of favorable causal impacts. Adoption of improved cultivars generated the largest, most consistent , positive yield and economic outcomes. Two agroecological practices, push-pull systems and the System of Rice Intensification, also repeatedly led to large positive impacts. These strategies have considerable potential to scale to reach more than 50% of smallholder farmers who plant staple crops. Significant barriers to adoption remain, however, and identifying ways to overcome barriers to scale these successful strategies will be critical to meeting Sustainable Development Goals 1 and 2 by 2030. 347 Annu. Rev. Environ. Resour. 2023.48:347-369. Downloaded from www.annualreviews.org Access provided by 74.69.166.205 on 11/14/23. See copyright for approved use.
Background: Developing high yielding varieties is a major challenge for breeders tackling the challenges of climate change in agriculture. The panicle (inflorescence) architecture of rice is one of the key components of yield potential and displays high inter- and intra-specific variability. The genus Oryza features two different crop species: Asian rice (Oryza sativa L.) and the African rice (O. glaberrima Steud). One of the main morphological differences between the two independently domesticated species is the structure (or complexity) of the panicle, with O. sativa displaying a highly branched panicle, which in turn produces a larger number of grains than that of O. glaberrima. The genetic interactions that govern the diversity of panicle complexity within and between the two species are still poorly understood.
Results: To identify genetic factors linked to panicle architecture diversity in the two species, we used a set of 60 Chromosome Segment Substitution Lines (CSSLs) issued from third generation backcross (BC3DH) and carrying genomic segments from O. glaberrima cv. MG12 in the genetic background of O. sativa Tropical Japonica cv. Caiapó. Phenotypic data were collected for rachis and primary branch length, primary, secondary and tertiary branch number and spikelet number. A total of 15 QTLs were localized on chromosomes 1, 2, 3, 7, 11 and 12 and QTLs associated with enhanced secondary and tertiary branch numbers were detected in two CSSLs. Furthermore, BC4F3:5 lines carrying different combinations of substituted segments were produced to decipher the effects of the identified QTL regions on variations in panicle architecture. A detailed analysis of phenotypes versus genotypes was carried out between the two parental genomes within these regions in order to understand how O. glaberrima introgression events may lead to alterations in panicle traits.
Conclusion: Our analysis led to the detection of genomic variations between O. sativa cv. Caiapó and O. glaberrima cv. MG12 in regions associated with enhanced panicle traits in specific CSSLs. These regions contain a number of key genes that regulate panicle development in O. sativa and their interspecific genomic variations may explain the phenotypic effects observed.
Background: Developing high yielding varieties is a major challenge for breeders tackling the challenges of climate change in agriculture. The panicle (inflorescence) architecture of rice is one of the key components of yield potential and displays high inter- and intra-specific variability. The genus Oryza features two different crop species: Asian rice Oryza sativa L.) and the African rice O. Glaberrima Steud). One of the main morphological differences between the two independently domesticated species is the structure (or complexity) of the panicle, with O. sativa displaying a highly branched panicle, which in turn produces a larger number of grains than that of O. Glaberrima. The genetic interactions that govern the diversity of panicle complexity within and between the two species are still poorly understood.
Results: To identify genetic factors linked to panicle architecture diversity in the two species, we used a set of 60 Chromosome Segment Substitution Lines (CSSLs) issued from third generation backcross (BC3DH) and carrying genomic segments from O. Glaberrima cv. MG12 in the genetic background of O. sativa Tropical Japonica cv. Caiapo. Phenotypic data were collected for rachis and primary branch length, primary, secondary and tertiary branch number and spikelet number. A total of 15 QTLs were localized on chromosomes 1, 2, 3, 7, 11 and 12 and QTLs associated with enhanced secondary and tertiary branch numbers were detected in two CSSLs. Furthermore, BC4F3:5 lines carrying different combinations of substituted segments were produced to decipher the effects of the identified QTL regions on variations in panicle architecture. A detailed analysis of phenotypes versus genotypes was carried out between the two parental genomes within these regions in order to understand how O. Glaberrima introgression events may lead to alterations in panicle traits.
Conclusion: Our analysis led to the detection of genomic variations between O. Sativa cv. Caiapo and O. Glaberrima cv. MG12 in regions associated with enhanced panicle traits in specific CSSLs. These regions contain a number of key genes that regulate panicle development in O. Sativa and their interspecific genomic variations may explain the phenotypic effects observed.
The shoot and root system architectures are fundamental for crop productivity. During the history of artificial selection of domestication and post-domestication breeding, the architecture of rice has significantly changed from its wild ancestor to fulfil requirements in agriculture. We review the recent studies on developmental biology in rice by focusing on components determining rice plant architecture; shoot meristems, leaves, tillers, stems, inflorescences and roots. We also highlight natural variations that affected these structures and were utilized in cultivars. Importantly, many core regulators identified from developmental mutants have been utilized in breeding as weak alleles moderately affecting these architectures. Given a surge of functional genomics and genome editing, the genetic mechanisms underlying the rice plant architecture discussed here will provide a theoretical basis to push breeding further forward not only in rice but also in other crops and their wild relatives.
Partial submergence of Oryza sativa deepwater rice elicits enhancement of internodal elongation, referred to as deepwater response, conferred by three types of genes, SNORKEL1/2 (SK1/2), SEMIDWARF1 (SD1), and ACCELERATOR OF INTERNODE ELONGATION 1 (ACE1). We investigated the presence and expression of these genes in the African cultivated rice Oryza glaberrima and the relationship between these genes and the deepwater response of O. glaberrima. In 49 of the 50 accessions tested, one or two SK genes were identified, which could be divided into three types of SK1 and four types of SK2. The accessions with the SK2 type whose expression was induced by submergence demonstrated rapid internodal elongation under submergence. In most of these accessions, submergence also increased the expression of SD1 and ACE1 genes. However, the accessions did not possess the haplotype of SD1 that is associated with high deepwater response in O. sativa. In contrast, they possessed the type of ACE1 gene similar to that in O. sativa deepwater rice. These results indicate that the molecular mechanisms underlying induction of deepwater response in O. glaberrima are similar to that found in deepwater rice of O. sativa and suggest that most O. glaberrima cultivars, including upland cultivars, can exhibit rapid internodal elongation under submergence.
Domestication of orphan crops could be explored by editing their genomes. Genome editing has a lot of promise for enhancing agricultural output, and there is a lot of interest in furthering breeding in orphan crops, which are sometimes plagued with unwanted traits that resemble wild cousins. Consequently, applying model crop knowledge to orphan crops allows for the rapid generation of targeted allelic diversity and innovative breeding germplasm. We explain how plant breeders could employ genome editing as a novel platform to accelerate the domestication of semi-domesticated or wild plants, resulting in a more diversified base for future food and fodder supplies. This review emphasizes both the practicality of the strategy and the need to invest in research that advances our understanding of plant genomes, genes, and cellular systems. Planting more of these abandoned orphan crops could help alleviate food scarcities in the challenge of future climate crises.
Domestication of orphan crops could be explored by editing their genomes. Genome editing has a lot of promise for enhancing agricultural output, and there is a lot of interest in furthering breeding in orphan crops, which are sometimes plagued with unwanted traits that resemble wild cousins. Consequently, applying model crop knowledge to orphan crops allows for the rapid generation of targeted allelic diversity and innovative breeding germplasm. We explain how plant breeders could employ genome editing as a novel platform to accelerate the domestication of semi-domesticated or wild plants, resulting in a more diversified base for future food and fodder supplies. This review emphasizes both the practicality of the strategy and the need to invest in research that advances our understanding of plant genomes, genes, and cellular systems. Planting more of these abandoned orphan crops could help alleviate food scarcities in the challenge of future climate crises.
Pyramiding of major resistance (R) genes through marker-assisted selection (MAS) is a useful way to attain durable and broad-spectrum resistance against Xanthomonas oryzae pv. oryzae pathogen, the causal agent of bacterial blight (BB) disease in rice (Oryza sativa L.). The present study was designed to pyramid four broad spectrum BB-R genes (Xa4, xa5, xa13 and Xa21) in the background of Basmati-385, an indica rice cultivar with much sought-after qualitative and quantitative grain traits. The cultivar, however, is susceptible to BB and was therefore, crossed with IRBB59 which possesses R genes xa5, xa13 and Xa21, to attain broad and durable resistance. A total of 19 F1 plants were obtained, some of which were backcrossed with Basmati-385 and large number of BC1F1 plants were obtained. In BC1F2 generation, 31 phenotypically superior genotypes having morphological features of Basmati-385, were selected and advanced up to BC1F6 population. Sequence-tagged site (STS)-based MAS was carried out and phenotypic selection was made in each successive generation. In BC1F6 population, potentially homozygous recombinant inbred lines (RILs) from each line were selected and evaluated on the bases of STS evaluation and resistance to local Xanthomonas oryzae pv. oryzae (Xoo) isolates. Line 23 was found pyramided with all four BB-R genes i.e., Xa4, xa5, xa13 and Xa21. Five genotypes including line 8, line 16, line 21, line 27 and line 28 were identified as pyramided with three R genes, Xa4, xa5 and xa13. Pathological study showed that rice lines pyramided with quadruplet or triplet R genes showed the highest level of resistance compared to doublet or singlet R genes. Thus, line 23 with quadruplet, and lines 8, 16, 21, 27, and 28 with triplet R genes, are recommended for replicated yield and resistance trials before release as new rice varieties. Further, traditional breeding coupled with MAS, is a solid way to attain highly effective BB-resistant rice lines with no yield cost.
Orphan crops, also known as minor crops, smart foods, and superfoods, have attracted great attention recently because of their unique ability to grow in resource‐poor marginal lands, and under harsh environmental conditions without any intensive agricultural care. These crops possess inherent tolerance against different abiotic stresses such as drought, salinity, cold, and heat. Recent advancements in genomic resources and high‐throughput phenotyping platforms have provided opportunities to explore the untapped potential of orphan crops to identify novel gene source(s) and mechanism(s) for developing abiotic stress‐tolerant crops. Moreover, genomics‐assisted investigations into the various physiological and molecular mechanism(s) could provide useful insights into stress tolerance mechanisms in these plants. Nevertheless, translating the hidden power of the tolerant gene pools from the orphan crops into major staple crops for enhancing their stress tolerance while maintaining yield is a challenging task. The contemporary tools of genomics can be used to unravel the secret of stress tolerance in orphan crops and employ these untapped genes for tailoring stress‐tolerant crop varieties to ensure global food security in the era of climate change. Deciphering the complexities of abiotic stress tolerance is a huge task and requires good model crops for investigation. Advancements in genomic technologies have made it possible to sequence and analyze a large number of orphan crops, which are known for their abiotic stress tolerance potential.
Rice today is food to half the world's population. Its history is inextricably entangled with the emergence of colonialism, the global networks of industrial capitalism, and the modern world economy. The history of rice is currently a vital and innovative field of research attracting serious attention, but no attempt has yet been made to write a history of rice and its place in the rise of capitalism from a global and comparative perspective. Rice is a first step toward such a history. The fifteen chapters, written by specialists on Africa, the Americas, and Asia, are premised on the utility of a truly international approach to history. Each brings a new approach that unsettles prevailing narratives and suggests new connections. Together they cast new light on the significant roles of rice as crop, food, and commodity and shape historical trajectories and interregional linkages in Africa, the Americas, Europe, and Asia.
Rice today is food to half the world's population. Its history is inextricably entangled with the emergence of colonialism, the global networks of industrial capitalism, and the modern world economy. The history of rice is currently a vital and innovative field of research attracting serious attention, but no attempt has yet been made to write a history of rice and its place in the rise of capitalism from a global and comparative perspective. Rice is a first step toward such a history. The fifteen chapters, written by specialists on Africa, the Americas, and Asia, are premised on the utility of a truly international approach to history. Each brings a new approach that unsettles prevailing narratives and suggests new connections. Together they cast new light on the significant roles of rice as crop, food, and commodity and shape historical trajectories and interregional linkages in Africa, the Americas, Europe, and Asia.
Rice, Oryza sativa L., is one of the most important cereal crops in the world, and its emergence as a domesticated subsistence plant drives much of the interest and research in archaeology in South and East Asia. The homeland of domesticated rice has been proposed as:
1 a specific area, such as India (Vavilov 1926; Ramiah & Ghose 1951), South China (Ding 1957), Southeast Asia (Spencer 1963) and the Yangtze valley in China (Yan 1982; 1989)
2 a biogeographic region, such as the so-called ‘belt region’ with a great diversity of Oryza species (Chang 1976), or
3 an ecological zone, such as coastal swamp habitats (Higham 1995).
Knowledge of rice domestication and its archaeological context has been increasing explosively of late. Nearly 20 years ago rice from the Hemudu and Luojiajiao sites (FIGURE 1) indicated that rice domestication likely began before 5000 BC (Crawford 1992; Lin 1992; Yan 1990). By the late 1980s news of rice from the south-central China Pengtoushan site a thousand years older than Hemudu began to circulate (Bellwood et al. 1992; Hunan 1990; Pei 1989). Undocumented news of sites having a median date of 11,500 BP with domesticated rice has recently made the rounds (Normile 1997). In addition, the first domesticated rice in Southeast Asia, once thought to be to be older than the first rice in China, is not as old as once thought (Glover & Higham 1996: 422; Higham 1995). Finally, wild rice ( Oryza rufipogon ) was reported to be growing in the Yangzi valley, well outside its purported original range, making domestication there plausible (Yan 1989; 1990; 1997). Significant progress continued to be made in the 1990s and unlike research on other major crops, the literature is generally not accessible to western scholars, with some exceptions (Ahn 1993; Crawford 1992; Glover & Higham 1996; Higham 1995; MacNeish et al . 1997; Underhill 1997).
The publications of the Hakluyt Society (founded in 1846) made available edited (and sometimes translated) early accounts of exploration. The first series, which ran from 1847 to 1899, consists of 100 books containing published or previously unpublished works by authors from Christopher Columbus to Sir Francis Drake, and covering voyages to the New World, to China and Japan, to Russia and to Africa and India. Gomes Eanes de Zurara (c.1410–1474) was a Portuguese writer appointed to chronicle the life of Prince Henry the Navigator (1394–1460) and the expeditions he sponsored. Zurara's chronicle of the discovery of Guinea appeared in this two-volume English translation in 1896–1899. The editors' preface includes an account of the voyages of exploration along the African coast sponsored by Prince Henry until 1448, together with biographical information about the author. Volume 1 contains chapters 1–40 of the Chronicle.
The Jola (Diola) are intensive wet-rice cultivators in the Lower Casamance region of Senegal. In this study, the author examines the reasons behind startling contrasts in the organization of agricultural tasks among three Jola communities located within a 45-kilometre radius from Ziguinchor. In Sambujat, situated in the non-Islamisized region south of the river, wet rice is a monocrop cultivated by both men and women. In Jipalom, in the Kajamutay region north of the river, Islam and cash cropping have been adopted; and in Fatiya, in the so-called 'Mandingized' region of the Kalunay, social relations have become hierarchical and this has had profound effects on the cropping system and on the division of labour. The author examines the shift of power relations over time, and their effects on the way in which production has been organized by age and gender, kin and class. Larger issues dealt with are Islamization, women's labour and the introduction of cash cropping. A concluding section places the history of Jola labour relations within the context of the political economy of Senegal.
In this groundbreaking work, Robert Baum seeks to reconstruct the religious and social history of the Diola communities in southern Senegal during the precolonial era, when the Atlantic slave trade was at its height. Baum shows that Diola community leaders used a complex of religious shrines and priesthoods to regulate and contain the influence of the slave trade. He demonstrates how this close involvement with the traders significantly changed Diola religious life.
Translation and edition. The additional documents, in translation, comprise a letter by Antoine Malfante, 1447, an account of the voyages of Diogo Gomes, c. 1456, and extracts from João de Barros, Decadas de Asia. This is a new print-on-demand hardback edition of the volume first published in 1937. Owing to technical constraints it has not been possible to reproduce the map of “North-western Africa in the fifteenth century” which appeared in the first edition of the work.
Journal of Interdisciplinary History 31.2 (2000) 315-316
Baum's superb study of the history of Diola religion is based on a thesis submitted more than twenty years ago. The reasons for the delay are obvious. There are few histories of traditional religious systems and of decentralized societies, which most observers regard as static. Baum challenges this idea, but, in the process, underlines the difficulties of compiling the history. Decentralized societies are not simple societies. They are more complex than state societies; traditions are highly localized; and communities differ. In addition, the Diola were secretive. Baum studied the small village group of Esulalu on the south bank of the Casamance river in southern Senegal, which numbered about 15,000 people, visiting it seven times. Though Baum uses written descriptions by explorers, merchants, missionaries, and administrators, most of his data comes from oral histories of families and religious shrines. In the end, he takes issue with many established ideas.
The first is the link between the slave trade and centralized states. When the Portuguese first arrived in upper Guinea in the fifteenth century, they found both states and stateless societies. Some were Malinke colonies; others were linked by trade to Mali. The lower Casamance was dominated by the Bainounk kingdom of Cassanga, the ruler of which was called the Casa Mansa. Though these kingdoms responded to the Portuguese demand for slaves, the long-range effect of the Atlantic trade is their decline and loss of control over the decentralized societies that proved to be effective slavers. The Diola moved northward from an area in what is now Guinea-Bissau and eventually absorbed most earlier inhabitants of the lower Casamance. Today they number about 500,00 people.
In Esulalu, the Diola defeated and absorbed earlier Bainounk inhabitants. The Bainounk were integrated rather than being sold, perhaps because the slave trade was limited in the sixteenth and seventeenth centuries but more likely because they were too numerous. They also resembled the Diola in many ways. Bainounk shrines were adopted, and a Bainounk became the priest-king of the most important shrine.
The priest-king was a ritual figure who had little actual power. Governance was in the hands of the shrines, which settled disputes and regulated such economic activities as palm-wine tapping, rice cultivation, and the hiring of labor. The Diola immigration intensified population pressure and led to increased conflict over rice paddies, oil palms, fishing zones, hunting areas. The early Diola generally ransomed prisoners, many of whom were young men caught in attempted cattle raids. Others were men and women taken in slave raids. During the seventeenth and eighteenth centuries, more and more prisoners were sold to agents of the Portuguese. New shrines were established to regulate the trade. Captives could not be mistreated; nor could they be sold before kin had a chance to search and ransom them. The slave trade stimulated conflict not only between village groups but also between villages and quarters. People went to their fields in groups and often armed.
The shrines provide Baum a window into Diola society. They were created in different ways, some borrowed from neighboring communities and others created as the result of dreams or visions by people who had spiritual gifts. The data that Baum culls from them enable him to question several popular theses. He questions Horton's distinction between traditional and universal religions, the former based on microcosmic views of the world, presenting a sophisticated Diola cosmology. He also questions whether traditional religions were static and whether they necessarily had a magical view of causality, as well as the notion that they had little idea of history. Though he has an excellent description of the penetration of Islam and Christianity in the nineteenth century, he does not ask whether the new religions influenced Diola views of their old religion.
Martin A. KleinUniversity of Toronto
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Les grands voyages et les transferts intercontinentaux de plantes cultivées ont eu des répercussions extrêmement importantes sur le développement des civilisations par action directe sur la prospérité de leurs agricultures et sur leurs régimes alimentaires. Il n'est que de rappeler le rôle joué par la Pomme de terre dans les pays tempérés et par le Maïs dans la zone chaude, rôle de briseurs de famine et de disette .
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