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Abstract
One of the most important constraints for agriculture is water limitation. More recently, global warming may be worsening this situation in most agricultural regions. Thus, it is quite relevant to understand the mechanisms that enable plants to cope with water deficit. Indeed, plants show a wide range of adaptations, at different levels, to drought stress. The present review describes strategies used by plants to adapt to low water potential at the physiological, biochemical and molecular levels. This review also describes several approaches carried out by breeders in order to obtain varieties of agronomically-important crops with improved drought tolerance, such as traditional breeding and those based on molecular markers for drought tolerance. Strategies involving genetic engineering are also detailed, some of which show great promise. It is concluded that a combination of the aforementioned strategies will be necessary for crop production under generalized water limitation in the near future.
... Osmotic cell potential can be accustomed by increasing the concentration of sugar which can decrease water potential of cells without inhibiting the function of the enzyme and does not reduce turgidity of the cell. Sugar accumulation under drought stress conditions helps to uphold the stability of the membrane, prevent and protect membrane fusion and; keep protein so as to remain functional [60,59,23,24,2] . ...
Maize is a cereal crop that has an imperative part of trades as well as a principal nutriment in several nations all over the globe. Its growth, production and productivity extremely influenced by drought stress. A study was conducted to examine the influence of drought condition on sugar and proline content in 80 genotypes including parents raised in half diallel crosses under irrigated and partial irrigated circumstances in RBD with two replications. Proline and sugar content was estimated to evaluate the potential of genotypes against drought. Upsurge in the content of sugar and proline among genotypes was investigated highly significant at 1% probability level. Among eighty maize genotypes, genotypes viz., IL1XIL4, IL3XIL5, IL2XIL5, IL2XIL11, IL7XIL11, IL9XIL10, IL8, IL5XIL11, IL1XIL7 and IL1XIL8 showed enhanced levels of sugar and proline content. Henceforth, these genotypes may be drought tolerant and could be used in varietal development programme to breed drought tolerant cultivar (s).
... Water availability is a big challenge in crop growth globally, and also for development, production, and climate change caused this deficiency of water. Thus, predicting bad situations of water shortage worldwide should be taken into consideration (Raza, 2019;Xoconostle, 2010). Drought is also one important abiotic stress that can have negative effects on crop growth and development such as physical damage, physiological and biochemical disturbance, and molecular changes which lead to abnormalities of metabolic processes, reduce plant growth, leading to plant death (Hussain, 2018;Fathi, 2016). ...
Sweet corn producers and industries require more reliable cultivars which could be accomplished by hybrid breeding. However, progressive phenological growth may be affected by different factors. In this paper, we analyze the key factors that determine the growth and yield of sweet corn. Environmental factors such as temperature and photoperiod were strong determinants of dates of flowering and harvest which are often crucial to yield in diverse climates and agricultural systems, besides the country's pedological conditions, especially soil fertility, affected phenological development. The effectiveness of fertilization in improving sweet corn growth performance was significantly influenced by the soil characteristics, the water supply, the genotype, and the agrotechnological factors. Therefore, genetic improvement of hybrids should be incorporated into the climate and soil elements to stabilize sweet corn yields in various agroecosystems. Decisions made in the sowing period are very significant, as up to 30% of the obtained yield may depend on making the proper choice. Deviation from the optimum date (either early or late sowing) may decrease yield. When deciding about the sowing date of maize, one needs to consider climate, soil quality, geographical location, temperature, weed infestation, sowing seed quality, and the ripening time of the hybrid to be produced.
... A water deficit will occur if there is not enough water available to satisfy a plant's needs. This water shortage is the result of a combination of factors, including salt stress and water scarcity, which have a negative impact on plant production (Xoconostle-Cazares et al., 2010). Plants have evolved several cellular responses to adjust their growth in environments with limited water. ...
Under both normal and stressful circumstances, plants produce reactive oxygen species (ROS). However, when environmental conditions are too unfavourable, excessive ROS is produced and the antioxidative defence mechanisms cannot handle the high amounts of ROS, which results in plant damage. The antioxidant defence system's enzymatic and non‐enzymatic components detoxify and scavenge ROS to lessen their harmful effects. The ascorbate‐glutathione (AsA‐GSH) route, also referred to as the Asada‐Halliwell pathway, entails four enzymes that are essential for the detoxification of ROS: AsA peroxidase (APX), dehydroascorbate reductase (DHAR), monodehydroascorbate reductase (MDHAR), and GSH reductase (GR). These enzymes work in conjunction with other plant defence mechanisms in addition to detoxifying ROS to shield plants from different abiotic stress‐related harms. Numerous studies on plants have shown that the up‐regulation or overexpression of these antioxidant enzyme genes enhances the AsA and GSH levels in response to abiotic stresses and helps plants to lower ROS levels. This article outlines the role of APX as a crucial enzyme in the AsA‐GSH pathway and the capacity of plants to withstand abiotic stress.
... Plant breeders have tested various breeding techniques to improve abiotic stress tolerance in crop plants [59,68−71] . The production of hybrid, mutants and transgenic plants are some of the well-known methods for this purpose [58,70] . The wide range of drought related genes in the plant genome has opened amazing opportunities for crop improvement. ...
Abiotic stresses, caused by climate change pose a huge threat to agriculture. In particular, climate change related drought stress will have large negative impact on crop growth, development and eventually production. As the changes in the weather patterns have a direct impact on farmers' capability to grow crops, the urgency of improving farmers' adaptive capacity should be addressed to minimize the potential negative impacts of climate change. Availability of adaptation technologies that would reduce crop production losses is of utmost importance in attaining climate change resilient crops. One potential adaptive measure is the use of crop varieties resilient to climate change related stresses. Various breeding technologies have been used to develop new durable crops, if not, enhanced or improve the ability of crops to survive under adverse environmental conditions, brought about by the changes in climate. One of the most sustainable strategies to mitigate these effects to agriculture is the development of climate resilient crops. Crops that can thrive under extreme weather conditions as effects of the changing climates. Conventional breeding may not be enough to develop new breeds of crops with better durability to abiotic stresses such as drought, salinity, submergence, high and low temperatures. Thus, other strategies as stand-alone or in combination with conventional breeding, are explored to enhance genetic variability for improving tolerance to abiotic stresses. These are the biotechnological approaches including marker assisted breeding, mutation breeding, genetic engineering and genome editing. These technologies offer a better future for developing climate change resilient crops.
... However, this comes with high costs, impacting overall fitness of the plant (for a critical review see Serraj and Sinclair 2002). Thus, these cellular responses need to be supported by systemic responses, such as a rapid closure of stomata, preventing further water loss (Xoconostle-Cázares et al. 2011). Both of these responses allow to evade the impact of the stress to a certain extent. ...
Stress resilience is central for plant survival. The appropriate adaptive response not only depends on the type of stress, but also on the context with other stresses, the developmental state of the plant, and the history of preceding stress experiences. The response to stress combinations cannot be a mere addition of the responses to the individual factors. For instance, heat stress requires stomatal opening to cool the leaf by increased transpiration, while drought stress needs stomatal closure to reduce water loss by transpiration. However, heat and drought are often coming in concert, such that the plant needs to reach a prioritised decision. Thus, the response to stress combinations constitutes a new quality transcending the addition of individual stress components. In other words: to survive under combined stress, plants need to render real decisions. We propose a model, where different stress inputs share one or more transducing elements, that can be recruited for different downstream pathways. Competition for these shared elements allows for such qualitative decisions, depending on the relative activities in upstream signalling of the individual stress components. Using different types of osmotic stress as paradigm I demonstrates, how signal modularity and differences in temporal sequence can generate qualitatively different outputs. Thus, plant-stress signalling makes use of a limited set of molecular players to generate, by specific rules for their combination and sequence, different “meanings”. This can be compared to human language, where information-bearing elements (words) are combined according to grammatical rules to generate a semantic space. (249 words)
Drought stress is the most critical threat to cultivated crops including tomato plants and poses a potential challenge to world food security. Melatonin (MEL) is a multifaceted signaling pleiotropic molecule involved in diverse plant processes. In this study, we explored the potential of foliar-applied MEL (50 or 100 μM) on two varieties (K-21 and S-22) of tomato (Solanum lycopersicum L.) under different drought levels. Drought stress was imposed using a reduced irrigation strategy based on re-watering at 60% and 30% of the field capacity. Drought stress resulted in a significant decrease in overall growth parameters, negatively affecting the photosynthetic parameters, disturbing the stomatal movement, and damaging the ultrastructure of the chloroplast. Moreover, severe drought stress level (30% FC) caused a significant decrease in rubisco activity by 35.46%, Fv/Fm by 36.07%, SPAD chlorophyl value by 48.85%, along with upsurge in malondialdehyde content by 153.23%, electrolyte leakage by 42.18%, and reactive oxygen species (ROS: H2O2 by 63.73% and O2·‒ by 48.89% in K-21 variety, while in S-22 the values of rubisco activity, Fv/Fm and SPAD chlorophyl value were decreased by 41.20%; 47.06%; 60.33%; while the malondialdehyde content, electrolyte leakage, H2O2 and O2·‒ were increased by 162.69; 60.67%; 73.39 and 59.96% respectively. Interestingly, foliar application of MEL (50 µM) alleviated the drought-induced damage (30% FC) by improved the activities of antioxidant enzymes (superoxide dismutase activity by 81.87 and 66.66%, peroxidase activity by 72.06 and 55.62% and catalase activity by 62.85 and 54.25%), enhanced proline content by 56.72 and 44.27%, protected the ultra-structure of chloroplast, maintained proper movement of stomata and substantially reduced the oxidative stress in K-21 and S-22 variety respectively. In conclusion, when tomato plants were subjected to drought stress, MEL treatment counteracted drought-induced negative impact by improving the growth attributes, photosynthetic efficiency, protects the ultrastructure of chloroplast and root tissues, improves the cell viability as well as boosts the antioxidant machinery, which ultimately promotes the growth, yield of the tomato plants. Notably, the impact of drought stress was more prominent in S-22 than K-21, however the counteracting effects of MEL under drought stress was pronounced in K-21 than S-22.
Agriculture in dryland regions is directly affected by climate change. In Afghanistan, climate-smart agriculture (CSA) improves productivity resilience and reduces greenhouse gas emissions (GHG). However, climate change, water shortage, population growth, and food insecurity are major challenges in developing countries such as Afghanistan. In the face of climate change, traditional agriculture methods need to be transformed into CSA that are capable of improving food production within the constraints of climate change. A review study was conducted to identify opportunities and challenges for CSA in Afghanistan. Among the many CSA technologies in Afghanistan, the review found, the use of drought resistance varieties, implementation of conservation agriculture, the use of Zai and Half-moon techniques for planting pits, moisture conservation, rainwater harvesting, watershed management, drip irrigation system, soil carbon sequestration, control erosion techniques, and climate forecast services are the best opportunities and as promising options for risk management and adaptation to climate change. Still, unfortunately, most of these options have not yet been implemented by Afghan farmers, just followed by researchers. In addition, CSA in Afghanistan faces several solvable challenges. Limited understanding of the CSA concept and framework, limited investment to develop and implement CSA technologies, inadequate communication between government, policymakers, farmers, climate change impacts, GHG, and traditional agriculture. The review recommended that CSA practices be suitable options for all stakeholders to increase income and ensure food security and sustainable agriculture by adaptation practices against climate change. This review provides new strategies and ideas for strengthening sustainable agriculture, food security, environmental protection, and mitigating the impact of climate change.
Rice, a primary staple, confronts a multitude of biotic and abiotic stresses. Drought and salinity, exacerbated by climate change and blast disease caused by Magnaporthe oryzae, significantly contribute to yield losses. To tackle the problems, two types of seaweeds-one known as Hypnea musciformis and another unknown-were collected from Saint Martin, Cox's Bazar, Bangladesh and then examined for the potential of their extracts to stimulate growth and improve resistance to drought, salinity and blast disease in rice. Molecular identification based on cytochrome C Oxidase subunit I (COI) gene sequence, the unknown seaweed was identified as Gracilaria tenuistipitata. Seaweed extracts were prepared from seaweed at different pH (8, 9, 10) and temperature (40, 50, 60, 70, 80°C) regimes. The laboratory and pot experiments were set up using a Completely Randomized Design (CRD), with three replications for each treatment. All trials were conducted ethically and data were analyzed using ANOVA followed by Duncan's Multiple Range Test (DMRT) to determine the statistical significance (p = 0.05) of treatment means. Priming rice seeds with the extracts significantly increased germination rates and seedling vigor. Furthermore, seedlings grown in media amended with seaweed extracts exhibited enhanced growth and chlorophyll content compared to the control. Seaweed extracts also demonstrated the ability to ameliorate drought and salt stress while protecting rice plants from the blast pathogen M. oryzae. Among the two seaweeds tested, G. tenuistipitata was found to promote higher plant growth and biotic and abiotic stress tolerance in rice compared to Hypnea musciformis. Optimal extraction conditions, particularly low temperature (40°C) and pH 9, were identified as key factors in maximizing the bioactivity of the extracts. From these results, it can be concluded that seaweed extracts, particularly those from H. musciformis and G. tenuistipitata collected from Saint Martin, Cox's Bazar, Bangladesh, could be utilized as potential bio-stimulants and stress alleviators in rice cultivation, contributing to improved growth and resilience in the face of environmental changes.
d o i. o r g / 1 0. 5 2 8 6 6 / e s j. 2 0 2 3. 0 1. 2 2. 1 2 الـعـراقـيــة الـجـامـعـة-التـربـيــة كــليـــة-والـعـلمـيــة الـتـربــويــة الـدراســات مجـلـة م 2023 أيـلـول-الحياة علوم-األول الـمـجـلـد-والعـشــرون الثاني الـعـدد Studying the effect of laser stress in combination with mannitol on some morphological parameters of cabbage (Brassica oleracea var L. capitata) In vitro Abstract : The main purpose of this work is to investigate the influence of Nd: YAG (neodymium-doped yt-trium aluminum garnet) green laser irradiation on mannitol-induced drought stress in white cabbage (Brassica oleracea var L. capitata) using in vitro technique. Seeds were surface sterilized by using 70% ethanol for 1 min followed by 2% of (NaOCl) for 15 minutes, then irradiated with five doses of green laser at different duration namely (0, 25, 50, 75, 100, and 125 seconds) and then germinated on MS basal medium for 14 days. After seeds germination, the germination percentage, number of shoots. explants-1 , shoots height (cm), and number of leaves. plantlets-1 was recorded. Results revealed that higher germination 100 % at (0 and 100 and 125 seconds) of laser treatment. Whereas (75 and 100 seconds) were superior in giving highest number of shoots. Explants-1 , shoots height and number of leaves. Concerning the effect of laser treatments in combination with mannitol osmotic stress, the results clarified that the highest callus fresh weight was (232.87 mg) at 60 g.l-1 of mannitol at 125 seconds of laser treatment, while 40 g.l-1 of mannitol in combination with (25, 50 and 125 seconds) recorded the highest callus dry weight (35.11, 33.6 and 33.95 mg) respectively. 158 Studying the effect of laser stress in combination with mannitol on some morphological parameters of cabbage (Brassica oleracea var L. capitata) In vitro .
The accumulation of abscisic acid (ABA) by detached and partially dehydrated wheat leaves is known to be inherited in a quantitative manner. The location of genes having a major effect on drought-induced ABA accumulation in wheat was determined using a set of single chromosome substitution lines and populations derived from a cross between a high-ABA- and a low-ABA-producing genotype. Examination of a series of chromosome substitution lines of the high-ABA genotype 'Ciano 67' into the low-ABA recipient 'Chinese Spring' showed that chromosome 5A carries gene(s) that have a major influence on ABA accumulation in a drought test with detached and partially dehydrated leaves (DLT). A similar DLT was used to examine ABA accumulation in a population of F2 plants and doubled haploid (DH) lines derived from the cross between 'Chinese Spring' (low-ABA) and 'SQ1' (high-ABA) in which the F2 population (139 plants) and DH lines (96 lines) were also mapped partially with molecular markers. Analysis of variance of ABA accumulation between and within marker allele classes in the F2 confirmed the location of a gene(s) regulating ABA accumulation on the long arm of chromosome 5A. MAPMAKERQTL showed the most likely position for the ABA quantitative trait locus (QTL) to be between the loci Xpsr575 and Xpsr426, about 8 cM from Xpsr426. A similar trend for high ABA accumulation was found in DH lines having the 'SQ1' allele at marker loci in the same region of chromosome 5AL, but the QTL effect was not significant. The function of the QTL is discussed.
Upland rice, produced by smallholder farmers, is the lowest-yielding rice production system. Drought stress is the most severe abiotic constraint in upland rice. Improving productivity of rice in the upland ecosystem is essential to meet rice food security needs of impoverished upland communities. In this context, breeding drought-resistant rice is an increasingly important goal. Numerous secondary characters have been suggested to help plant breeders in their selections, but most of these traits are not used in selection, as they are not practical for selection purposes, exhibit low heritability, or are not highly correlated with grain yield. Standardization of drought screening has been shown to increase the heritability of yield under stress to values similar to those obtained for yield in well-watered conditions. It has now been demonstrated that drought tolerant upland s can be bred by directly selecting for yield in stress environments. The use of molecular markers to perform selection may eventually provide plant breeders with more efficient selection methods. To date, many quantitative trait loci (QTL) for drought resistance have been identified in rice, but few are suitable for use in marker-assisted selection. However, large-effect drought resistance QTL have now been identified and may enable effective use of marker-assisted selection for drought resistance.
Drought is one of the main constraints for common bean (Phaseolus vulgaris L.) production in Latin America. The aim of this work was to identify upregulated genes in the drought-tolerant common bean cv. Pinto Villa, grown under water-deficit conditions. Twenty-eight cDNAs representing differentially-expressed mRNAs in roots and/or leaves were isolated via suppression subtractive hybridisation. Their expression profiles in plants under intermediate and severe dehydration stress were tested. Three cDNAs corresponded to genes already described as associated to drought stress in P. vulgaris, 12 were known P. vulgaris sequences without previous association with drought response, and 13 were new P. vulgaris sequences. Analysis of the deduced proteins encoded by the cDNAs revealed putative functions in cellular protection, sugar metabolism, and protein synthesis, folding and turnover. Additionally, a new member of group 3 late embryogenesis abundant (LEA) genes (PvLEA3) was cloned and its complete sequence was obtained. Given the lack of reports comparing expression of dehydration-responsive genes in bean cultivars with different response to drought, the expression of PvLEA3 transcript in five bean cultivars from different origin was analysed. The induction of PvLEA3 was directly associated with the level of drought tolerance in the cultivars studied.
The global wheat production by year 2020 could be increased by 40% provided there is a good integrated multidisciplinary wheat research program optimally funded by either public or private sectors. More emphasis needs to be placed on: 1) Improving yield potential; 2) Durable disease resistance; 3) Increasing abiotic stress tolerance; 4) Adopting better conservation systems. There are roles for both conventional plant breeding and biotechnology supported by other disciplines to achieve this goal.
Earlier studies found that cotton (Gossypium hirsutum L.) cotyledons contain several mRNAs which are more abundant during late embryogenesis than in mid-embryogenesis or early germination. They are here termed 'Late embryogenesis-abundant' mRNAs, encoded by Lea loci. Complementary DNA clones for 18 such mRNA sequences, defined at a hybridization criterion of Tm-15°C, were identified in a mature embryo cDNA library by differential cDNA hybridization. At a lower hybridization criterion, some sequence homology was found within several of these cloned Lea mRNA sequences. Each Lea mRNA sequence comprises 0.04-1.3% of mature embryo poly(A)(+) mRNA, a level ten-fold to several hundred-fold higher than in young embryo or 24 h seedling poly(A)(+) mRNA. Of 18 Lea mRNA sequences examined in cultured young embryos, the level of at least 13 are specifically increased by exogenous abscisic acid (ABA), several to a level near that in normal mature embryos. However, the abundance of several of the sequences does not appear to be significantly modulated by ABA. The LEA polypeptides encoded by 10 Lea mRNA sequences were identified by hybrid-arrested translation. They include most of the late embryogenesis-abundant, ABA-inducible, polypeptides previously identified. Preliminary results suggest that many of the individual Lea mRNA sequences are transcribed from 1-3 genes in each of cotton's two subgenomes.
LEA proteins are late embryogenesis abundant in the seeds of many higher plants and are probably universal in occurrence in plant seeds. LEA mRNAs and proteins can be induced to appear at other stages in the plant's life by desiccation stress and/or treatment with the plant hormone abscisic acid (ABA). A role in protecting plant structures during water loss is likely for these proteins, with ABA functioning in the stress transduction process. Presented here are conserved tracts of amino acid sequence among LEA proteins from several species that may represent domains functionally important in desiccation protection. Curiously, an 11 amino acid sequence motif is found tandemly repeated in a group of LEA proteins of vastly different sizes. Analysis of this motif suggests that it exists as an amphiphilic α helix which may serve as the basis for higher order structure.
Many of the world's rice-growing regions lack adequate irrigation facilities, and drought frequently reduces yield. This paper reviews drought-resistance traits in rice and their quantitative trait loci (QTLs), with emphasis on CT9993/IR62266, one of the most widely studied mapping populations, and suggests ways to develop cultivars that will perform well in drought-prone environments. Information about the type of drought faced in the target region – particularly the timing of the drought (late season terminal drought, early stage vegetative drought, and intermittent drought) and the intensity of the drought – are important in determining the specific plant traits required to improve drought resistance in rice. Most of these traits are related to drought avoidance strategy, so that the drought-resistant genotypes are able to maintain better internal water status, either by taking up more water through a better root system or by reducing the rate of plant water use. We identified and listed a number of QTLs for many drought-resistance traits, such as deep roots. We identified four key genomic regions on chromosomes 1, 4, 8, and 9 on which are co-located a number of QTLs for traits considered to be directly or indirectly responsible for grain yield under stress. These regions, once they have been more finely mapped, appear promising for eventual use in marker-assisted selection for development of drought-resistant rice varieties. In addition to selecting for specific traits or specific genomic regions, screening under managed drought conditions on the basis of yield itself or on spikelet fertility adjusted for flowering time appears useful, because of the relatively high degrees of heritability of these characters, for the development of drought-resistant rice cultivars, and it is currently practiced in some breeding programs.
summaryDrought strongly affects cereal yield in several regions of the world. Plant growth and plant water status in response to soil water deficit play an important role in tolerance to drought and in yield stability. In order to investigate the relationship between plant growth and water relations, 187 barley (Hordeum vulgare L.) recombinant inbred lines from a cross between two Mediterranean varieties, Tadmor and Er/Apm, were studied in a growth chamber for RWC, number of leaves on the main tiller (NL), number of tillers (NT) and total shoot fresh and dry biomass (TSFM and TSDM). Measurements were made at the beginning of tillering on well watered plants and at a soil moisture content of 14% of field capacity. A negative phenotypic correlation between RWC and growth parameters was obtained in both treatments. Under water stress, a negative genetic correlation was also found between the same characters. QTLs involved in RWC, NL and TSFM variation were positioned on a RFLP-RAPD genetic map. Different DNA regions involved in constitutive and water stress responses were detected. In the stress treatment, one region on chromosome 1 was involved in RWC and NL variation giving a genetic basis to the phenotypic correlations found. Separated map positions were also found for RWC and NL. Epistatic interactions between several QTLs and between QTLs and other markers were detected only in the water stress treatment, suggesting that some chromosomal regions might be involved in the regulation of the expression of the traits under water stress. This work suggested that even if some parameters are strongly correlated, finding QTLs for only one trait is not sufficient to detect all the candidate regions which might be involved in the control of the correlated traits. The results of localization and co-localization of QTLs are physiologically interpreted.
The authors evaluated 57 parental inbred lines of maize hybrids disseminated in Southwest China for drought tolerance under drought-stressed and well-watered conditions. Multiple regression analyses between drought tolerant coefficients of the grain yield per plant and 15 morphological and physiological traits measured from a subset of 12 selected lines, identified traits 1 and 5, which were important for drought tolerance, at the seedling and reproductive stages respectively. Gene effects, combining abilities, and heritabilities of these traits were estimated using generation mean and diallel cross methods. Dominance effect was more important than additive effect for the plant height, anthesis-silking interval (ASI), root weight, and the grain yield per plant, whereas, they were about equal for the leaf emergence rate. The variances of special combining ability (SCA) were about double that of the general combining ability (GCA) for plant height, ASI and grain yield per plant, although they were about equal for leaf emergence rate and root weight. Narrow sense heritabilities of the five traits for the reproductive stage were not high (12.8–29.6%), although broad sense heritabilities for plant height, ASI, and grain yield were as high as 70–85%. A segregating population consisting of 183 F2 plants from the cross N87–1 (drought tolerant) × 9526 (susceptible), was genotyped at 103 SSR loci and the F2:4 families were evaluated under two water regimes. Twelve quantitative trait loci (QTLs) (two for plant height, five for ASI, four for root biomass, and one for grain yield) were identified, most of which had overdominant gene action. Some chromosomal regions, such as those linked to markers umc1051 (bin 4.08), umc2881 (bin 4.03), and phi034 (bin 7.02), had overlapping QTLs.