International Journal of Plant Production

Published by Springer-Verlag
Online ISSN: 1735-6814
Publications
Article
Summer maize (Zea mays L.) is one of the dominant crops in the North China Plain (NCP). Itsgrowth is greatly influenced by the spatial-temporal variation of climatic variables, especially solar radiation, temperature and rainfall. The WOFOST (version 7.1) model was applied to evaluate the impact of climatic variability on summer maize yields using historical meteorological data from 1961to 2000. The model was calibrated and validated using data from field experiments conducted duringthe period 1998-1999 and simulations were run to analyses the climate impact. Simulated potential yield ranges from 7.7 to 10.0 Mg ha-1, with an increasing trend from south to north, while rainfedyield ranges from 4.3 to 8.1 Mg ha-1, and with an increasing trend from the middle to the north and south of NCP. Gaps between potential and rainfed yields also decreased from the middle to the north and south. The pattern of potential yield was mainly attributed to the distribution of solar radiation and temperature, whereas rainfed yield was mainly influenced by the distribution of rainfall.Interannual variability n of potential yield is small, and was closely related to the variation of solarradiation, while rainfed yield varied greatly, especially in the middle of the plain, where the rainfall is lowest. Combined with consistent research results of winter wheat, results of this study offer scientificbasis for policy makers and researchers concerned with the management of food marketing decisions and water resource reallocation
 
Article
The Huang-Huai-Hai (3H) Plain is one of the most important winter wheat production areas in China. In this paper, the relationship between climate factors, growth duration and yield of winter wheat from 1980 to 2013 in the 3H Plain was examined to reveal the responses of winter wheat growth duration and yield to global warming. The results showed that daily average, maximum and minimum air temperatures during the winter wheat growing season increased by 0.43, 0.35 and 0.54 °C every 10 years, respectively, on average across the whole region in the past 30 years, although temperatures varied with different spatial distributions. Historical changes in winter wheat phenology have been observed across the 3H Plain since 1990s in that the vegetative growth period of winter wheat shortened by 4.6 days, the reproductive growth period increased by 1.8 days and the whole growth period was shortened by 2.9 days per 10-year period. The changes in the growth period were significantly negatively correlated with minimum temperature increases. The 1 °C minimum temperature increase shortened the vegetative growth period of winter wheat by 4.5 days. Accounting for agricultural technical improvement and other non-climatic factors, an average temperature increase of 1 °C enhanced winter wheat yield by 2.1% in the northern plain and decreased yield by 4.0% in the southern plain. We found an average temperature during the winter wheat growth season of 8.6 °C as the yield variation threshold, and the yield would decrease above this threshold in this region.
 
Location of the study area East Africa in the African continent (a), eight rainfall zones of East Africa (R1-R8), overlaid on elevation and meteorological stations (black dots) (b)
Intensities of dry and wet months based on 3-month (top row), and 12-Month (bottom row) SPEI over East Africa during the period 1981-2017
Box and whisker plots of mean annual yields of maize crops for the five East African countries during the period 1961-2017 (red dots indicate the outlier yields in each country)
SPEI classification for drought and flood events (Vicente- Serrano et al., 2010)
Article
East African countries (Uganda, Kenya, Tanzania, Rwanda, and Burundi) experience extreme rainfall phenomena such as droughts, floods, or wet events that usually impact negatively on agriculture. In this regard, the Standardized Precipitation Evapotranspiration Index (SPEI) is employed to assess the occurrence of agricultural drought and wet events based on 3-month and 12-month intervals over the period 1981–2017. Changes in maize yields with rainfall and temperature are analyzed using multi-regression techniques after detrending. The Modified Mann–Kendall test (m-MK) was used to examine the trends in yields and maize production area. The sensitivity index of maize crop yield (MCSI) is expressed as a reduction in maize yields/harvest caused by climate variations or extreme events. The results revealed higher frequencies of drought and wet events in a 3-month SPEI, while a 12-month SPEI presented more distinctive drought and wet events. Most agricultural regions in East Africa (EA) experienced between 43 and 47 months of moderate drought events, 20–23 months of severe droughts, and 11–9 months of extreme drought events during the period 1981–2017. Meanwhile, the wet events of 1997/1998, and 2015/2016 were fully revealed by both 3-month and 12-month SPEI, showing the robustness of SPEI in capturing drought and wet conditions over EA. Statistical crop models revealed that climate variability explained maize yield by approximately 63.0%, 57.0%, 60.0%, 56.0%, and 50.0% for Uganda, Kenya, Tanzania, Rwanda, and Burundi respectively. Except for Rwanda, m-MK showed that maize yields were statistically significantly increasing at a rate of 217.1, 88.9, 143.0, 52.0, and 53.0 kg/ha/year for Uganda, Kenya, Tanzania, and Burundi respectively. MCSI value of 1.0 was revealed in rainfall zone 4, and 0.95 for rainfall zone 5, as compared to 0.85 reported for each of rainfall zones 3 and 8. This implies that the former rainfall zones are more susceptible to extreme drought events or variations than the latter zones. Measures such as irrigation, rainwater harvesting, early warning systems for drought and wet events, and post-harvest handling of crops utilizing drying plates are recommended to adapt to the effects of climate variability.
 
Article
The expression pattern of TomPRO2 and LaPA1 genes in two tomato (Lycopersicon esculentum) cultivars named as Isfahani and Shirazi under in vitro salt stress were investigated. Four to six weeks old in vitro grown seedlings were transferred on MS medium containing 0, 80 and 160 mM NaCl and untreated plants were used as control. RNA was extracted from root and leaf and then cDNA was synthesized. Semi-quantitative analysis of TomPRO2 and LaPA1 expression using specific primers showed that with increasing of NaCl concentration from 0 to 160 mM, the expression level of TomPRO2 and LaPA1 genes in roots of both tomato cultivars did not change significantly. In leaf TomPR2 gene expression decreased significantly at 160 mM NaCl. At the same concentration of NaCl (160 mM) LaPA1 gene expression in leaf increased significantly. Based on the obtained results, TomPRO2 and LaPA1 genes have different expression patterns under in vitro salt stress in tomato root and leaf. However, both genes have a role in response to salt stress.
 
Article
Adoption of water-saving cultivation strategy for cereal crops benefits development of the sustainable agriculture worldwide. In this study, the effects of water supply on agronomic traits, ABA contents, drought response-associated physiological parameters, and expression patterns of the ABA receptor family genes during late stage were investigated. Under normal irrigation condition (NI, with irrigations performed prior to seed sowing, and at stages of jointing and flowering), the wheat cultivars, namely, the drought tolerant Cangmai 14 and the sensitive Jimai 325, displayed comparable agronomic traits (i.e. yields, yield components, and water use efficiencies), ABA contents, and the physiological traits associated with drought stress (i.e., proline and soluble sugar contents, and photosynthetic parameters). Under deficit irrigation (DI, without irrigation at flowering stage compared with NI), Cangmai 14 was much better on the agronomic traits, ABA contents, and the drought response-associated traits at late stage than Jimai 325. These results suggested that the improvement of drought response-associated traits contributed to the enhanced yield formation capacity of the drought-tolerant cultivars. Expression analysis on ABA receptor genes (i.e., PYL family ones) involving ABA signal perception indicated that TaPYL3, TaPYL5 and TaPYL8, three of the PYL family members, modified expression in the tested cultivars upon modified water supply copnditions, with more transcripts detected under DI than NI. Moreover, the expression levels of these genes were all shown to be higher in Cangmai 14 under DI than in Jimai 325. Transgene analysis on TaPYL3 validated that this gene exerted positive roles in modulating biomass production and photosynthetic function of plants under drought treatment. These results suggested the essential function of the ABA signaling genes in modulating plant drought response, whose enhanced transcription efficiencies positively impact on the drought response-associated physiological process, biomass production, and the yield formation capacity of wheat plants treated with DI through possibly an ABA-dependent pathway.
 
Article
Limited studies have been conducted to assess key yield-determining processes and their inter-relationships in okra under both nitrogen (N) poor as well as optimum growing environments on a set of contrasting genotypes. Therefore, in this study, we analyze the yield formation in two diverse genotypes of okra (Sabz Pari ‘SP’ and Arka Anamika ‘AA’) across seven contrasting N environments (0–300 kg ha⁻¹) and to determine effects of genetic (G), environmental (E) and their interaction (G × E) on a set of traits relevant to vegetative growth, onset of reproductive cycle, pod characteristics, and yield. The effects of G, E, and G × E were significant for majority of traits. Ranking of genotypes changed across the environments for most of the traits indicating a cross-over type G × E interactions. Majority of traits showed differential response to varied N availability. Mean values of plant height, canopy diameter, leaves plant⁻¹, leaf area plant⁻¹, stem girth, internodes plant⁻¹, length of internode, pod length, pod diameter, and pod yield enhanced with rising N (50–300 kg ha⁻¹). However, pod fresh weight and number of pods plant⁻¹ declined with N availability above 150 kg ha⁻¹. The onset of first flowering delayed with decline in N availability and vice versa. Late maturing genotype AA indicated a better yield potential across N environments by producing 50.96% more yield over early maturing genotype SP. There existed significant inter-relationships among most of the traits. Four traits including leaf area plant⁻¹, pod diameter, pod fresh weight and number of pods plant⁻¹ explained most of the variance (97.4%) in pod yield. It was concluded that gain in these parameters may lead to an increase in pod yield. Our approach could be useful in developing an indirect selection criterion for yield improvement in okra and could provide a theoretical framework for breeding programmes in developing an ideal genotype.
 
Relationship between chlorophyll a content and maximum quantum yield of PSII (F v /F m ) in PT1 rice treated with 0, 9.4, 11.8 and 24.1 mM KNO 3 subsequently exposed to 200 mM NaCl salt stress for 4 days. Error bars represent by ±SE.
Relationship between photon yield of PSII (Φ PSII ) and net photosynthetic rate (P n ) in PT1 rice treated with 0, 9.4, 11.8 and 24.1 mM KNO 3 subsequently exposed to 200 mM NaCl salt stress for 4 days. Error bars represent by ±SE.
Sodium (Na + ), potassium (K + ) ions and Na:K ratios in the root and leaf tissues of PT1 rice treated with 0, 9.4, 11.8 and 24.1 mM KNO 3 subsequently grown under 200 mM NaCl salt stress for 4 days.
Article
Potassium is a major nutrient which may play an important role in many processes such as ion homeostasis in plant cells and osmotic adjustment of guard cells during stomatal opening and closing. Pathumthani 1 (PT1) rice has been reported as being a salt sensitive cultivar and has been selected as a model plant in this study to investigate the possibility of improving the osmotic potential, pigment stabilization, photosynthetic efficiency and growth characteristics of this plant under salinity stress by potassium nitrate (KNO3) application. Sodium ion accumulation in root and leaves of KNO3 (11.8 mM) treated plants declined as compared to the control plants. In control plants, however, due to decline in potassium ion content, the Na+/K+ ratio increased significantly. A positive relation between Na+ accumulation and osmotic potential was found. Osmotic potential (Ps) in the root and leaf tissues of PT1 rice treated with 11.8 mM KNO3 was maintained at low levels, which was accompanied with the stabilization of photosynthetic pigments, high photosynthetic performance and better growth characters under 200 mM NaCl. The photosynthetic ability in plants with KNO3 application was positively related to plant dry weight. Exogenous KNO3 application to rice crops may play a vital role as a short-gun technique for the improvement of salt tolerance.
 
Article
High temperature reduces the pollen viability and silk receptivity of corn resulting in poor seed set and reduced yield. Continuously increasing temperature and less frequency and distribution of rainfall coupled with usual canal–closure particularly in Pakistan have significantly been decreasing the grain yield. This problem could be overcome by developing heat tolerant maize hybrids. For this purpose, five heat tolerant (lines), five heat susceptible (lines) and four heat susceptible (testers) corn inbred lines were hybridized artificially in a line × tester mating design. The 40 hybrids and 14 parents were evaluated for heat tolerance under moderate temperature field conditions (by sowing on March 31) using triplicated randomized complete block design during spring 2004. Large differences in heat units (111 to 326) utilized by the parents and crosses under normal and moderate temperature conditions to mature physiologically suggested that inbred lines as well as crosses were photosensitive as they were not utilizing similar thermal units in both the environments. Highly significant differences (P ≤ 0.01) were observed among 54 corn genotypes, 14 parents, 40 crosses, parent vs crosses and interaction term of lines × tester (L × T) for 14 maize plant traits. The inbred lines L1, L2, L3, L5 (lines), T1, T3 (testers) and hybrids L1×T3, L2×T4, L3×T3 and L5×T1 were proved to be the excellent combiners with high GCA and SCA effects respectively, for most of the traits. The dominance type of gene action was observed to be predominant for all the traits. The proportional contribution of lines was more for seven very crucial parameters. The estimates of heritability in broad sense were high for all the traits. Hybrid breeding is suggested as hybrid plants have higher capacity to tolerate heat stress in field conditions than their parents.
 
Monthly average rainfall (mm) and temperature (ºC) at the experimental spot in 2012 and 2013 and planting/harvest times of the two crops during growth period. (1) Shading indicates that the crops are growing in the field; (2) Wheat intercropped with maize has a co-growth period of almost 45 days.
Diagram showing the arrangement of wheat intercropped with maize (A) and sole wheat (B) in the field plot.
Grain yield affected by cropping systems and P application rates.
Harvest index of dry matter and Phosphorus.
Article
Intercropping often results in increasing production than sole per unit land area, but the underlying mechanisms are poorly understood. Plants showed different physiological characteristics in intercropping and sole. However, less information was shown the relationships between plant aboveground biomass (AB), phosphorus accumulation (PB) and remobilization and the yield advantage. Here, field experiments were designed as split plot and carried out in 2012 and 2013 with three P levels (0, 40 and 80 kg P ha⁻¹) in wheat (Triticum aestivum L.)/ maize (Zea mays L.) relay intercropping and sole. The study measured grain yield, AB and P accumulation and remobilization of wheat. Averaged grain yield of intercropping wheat increased 3.9 Mg ha⁻¹ in 2012 and 2.7 Mg ha⁻¹ in 2013 compared with that of the corresponding sole and the grain yield of intercropping wheat changed with the border row (BR) > the inner row (IR) > the sole wheat (SR), the grain yield in BR was contributed by 58.2% to intercropping wheat. The PA was consistent with AB accumulation, which in intercropping was higher than that in sole over the entire growing season. Close correlations between yield and AB remobilization and P remobilization were observed. The yield of BR was higher from 39.3% to 88.0% than that of SR wheat, as mainly attributed to more AB and P accumulation across the whole growing season and more remobilization from pre-anthesis to grain filling stage. More than 40 kg P ha⁻¹ did not result in any further increasing in yield and did not enhanced the physiological processes associated with AB and P remobilization, indicating that P fertilizer and agronomic management should be intensified synchronously in field to achieve high yield and sustainability. © 2017, GORGAN UNIV AGRICULTURAL SCIENCES AND NATURAL RESOURCES. All rights reserved.
 
Article
In many crops, the exogenous application of phytohormones or other chemicals can improve grain yield via modulation of carbohydrate metabolism in source and sink tissues. However, the issue is yet to be investigated thoroughly in soybean. In a field experiment, we applied auxin (indole acetic acid, IAA), cytokinin (benzyl amino purine, BAP), gibberellic acid (GA), nano-TiO2 and sucrose to soybean plants from the stage of flowering to the end of pod proliferation; and measured diurnal carbohydrate metabolism at pod filling, as well as yield related components upon harvest. Auxin appeared as the most effective treatment in reducing pod abscission by 32%, and enhancing seed size and number by 5% and 50%, respectively. The auxin-treated plants also showed an increase of about 16% in biomass, 52% in carbohydrates (leaves and pods) and 32% in pod alkaline invertase activity. Principal component analysis (PCA) indicated that carbohydrate-related parameters at sunset and sunrise correlate with yield, suggesting that diurnal photo assimilate availability—in the form of sucrose—and the nocturnal re-mobilization of starch play vital roles in yield enhancement. Of the other investigated compounds, sucrose, nano-TiO2 and GA reduced flower abscission with slight effects on yield, while cytokinin enhanced pod abscission. Altogether, auxin seems to increase the crop yield via not only the reduction of pod abscission but also the enhancement of carbohydrate metabolism in both source and sink tissues.
 
Article
Foliar spray of growth promoters significantly ameliorated the harmful effects of environmental warming and nutrient deficiency on growth, development and yield of major field crops. So, the current experiment was carried out to evaluate the potential effects of five growth promoting substances, including Moringa leaf extract, Polydol, Multisol, Classic and Asahi star along with water and no spray on growth indices, dry matter assimilation, seed cotton yield and related traits as well as chlorophyll scores of cotton var. MNH-886 under a semi-arid environment of Pakistan. On average bases, the results indicate that exogenous spray of growth promoters enhanced leaf area index by 20.0–26.0%, growth rate by 15.0–21.0%, dry matter partitioning by 15.0–21.0%, sympodial branches by 22.0–33.0%, harvested bolls by 46.0–48.0%, boll weight by 28.0–30.0% and total chlorophyll contents by 15.0–25.0% relative to control treatment. Due to improved morphological and yield contributing traits, the exogenous spray of promoters also increased the seed cotton yield by 21.0–33.0% and net benefit by 50.0–68.0% as compared to control. In conclusion, the MLE, being a cheaper source, could ameliorate the damages imposed by environmental warming and nutrient deficiency, leading to high cotton productivity. The farmers across the world can get high yield of cotton by foliar spray of MLE.
 
Article
This work aimed to study the intrinsic tolerance of Greek lentil accessions to imazamox herbicide by combining bioassays, pot and field experiments. Initially, 31 genotypes were evaluated in Petri dish bioassays for their tolerance to six concentrations of imazamox. The average root length of 10 lentil seedlings/dish at seven days after herbicide application was used for non-linear regression analysis and the GR50 values (the amount of the herbicide required for 50% root length reduction of the seedlings) were estimated to calculate the resistance ratio (R/S) of each cultivar. The results of the in vitro test clued the selection of nine accessions for further study in pot experiment, to assess their tolerance to four rates [0 (control), 20, 30, 40 g ai ha-1] of imazamox post-emergently applied at the seven true-leaf stage (V7 stage). Five weeks after treatment, the number of survived plants was recorded and the above-ground dry weight was determined in each pot. There was no direct correlation in the results of in vitro test and the pot experiment, suggesting no matching between the two methods. The evaluation of five accessions (cultivars with high commercial interest and accessions sporting tolerance in pot experiment) in field experiment demonstrated different but increased susceptibility to imazamox. Specifically, compared to the untreated control, the imazamox treatments reduced plant growth, delayed flowering and maturity and reduced yield, dry weight, 1000-seed weight and harvest index. Yet the protein concentration was increased in herbicide treatments. The findings of the study showed clearly that the evaluated lentil accessions lack genes with resistance to imazamox and different methods have to be used for assessing any potential tolerance. © 2016, Gorgan Univ Agricultural Sciences and Natural Resources. All rights reserved.
 
Article
Achieving a high yield is an ongoing major challenge to meet China’s increasing food demand. The N accumulation characteristics of high-yield spring maize are likely different from those of conventional-yield spring maize. A 2-year field experiment was conducted to investigating the N accumulation characteristics of high-yield (HY) (> 15 t ha⁻¹) spring maize in comparison with spring maize of medium yield (MY) and low yield (LY). The maximum N stage accumulation appeared between stages V6 and V12. N stage accumulation of LY decreased rapidly after the V12 stage, while N stage accumulation of HY remained high until the R2 stage and was two times that of LY at the R2 stage. The percentage contribution of N stage accumulation to the total accumulation was lower for HY than for LY during the vegetative stages (VE to VT), but higher for HY than for LY during the reproductive stages (VT to R6). The N remobilization amount in different organs was higher for HY than for MY and LY. The total apparent contribution to grains of HY (58.1%) was lower than that of MY (60.2%) and LY (75.5%), suggesting that most of the final grain N of HY was directly derived from the root system supply during the reproductive stages. Overall, these results indicated that maintaining a sufficient N supply during the growing stages, especially the reproductive stages, can increase the amount of N uptake, delay leaf senescence and maintain high photosynthetic activity, leading to a high yield.
 
Article
Repeated application of manures to agricultural soils could cause the accumulation of phosphorus (P) in soils. However, it is unclear if manure P can behave similar to P in soluble fertilizers in accumulation Olsen-P (0.5 mol L -1 NaHCO 3 at pH 8.5) in soils. A long-term wheat-maize rotation experiment was conducted to investigate the effects of repeated application of manures on P accumulation in soils. The results showed that excessive or residual P in soils led to increase of Olsen-P in soils, which could be predicted accurately by initial concentration of Olsen-P in soils, P fertilization rate, crop yield, soil pH and cultivation time. The effects of application of K fertilizers or maize straw to soils or replacement of maize with soybean in wheat cropping systems were not significant on soil Olsen-P accumulation. The accumulation rates of soil Olsen-P were governed by P application rates of soluble P fertilizers and/or manures. Similar trend of Olsen-P accumulation was found in soils with soluble P fertilizers only or plus manures P, which supplied evidence that behaviour of manure P in long-term field soils is similar to inorganic P fertilizers and are helpful for the best management of soil P in agricultural production and environment protection.
 
Leaf greenness of sesame at 45, 85, and 125 days after sowing (DAS) in 2018 and 2019. The P0, P1, P2, and P3 represent the paclobutrazol treatments, Control, 100 mg L −1 , 200 mg L −1 , and 300 mg L −1 , respectively. Means are averaged over three replicates
Leaf area of sesame plants at 45, 85, and 125 days after sowing (DAS) in 2018 and 2019. The P0, P1, P2, and P3 represent the paclobutrazol treatments, Control, 100 mg L −1 , 200 mg L −1 , and 300 mg L −1 , respectively. Means are averaged over three replicates
Biomass partitioning of sesame plants at 45, 85, and 125 days after sowing (DAS) in 2018 and 2019. The P0, P1, P2, and P3 represent the paclobutrazol treatments, Control, 100 mg L −1 , 200 mg L −1 , and 300 mg L −1 , respectively. Means are averaged over three replicates
Linear regression analysis for paclobutrazol vs seed yield of sesame. The 1.0, 2.0, 3.0, and 4.0 represent the paclobutrazol treatments, Control, 100 mg L −1 , 200 mg L −1 , and 300 mg L −1 , respectively
Article
Several biotic and abiotic stresses significantly decrease the biomass accumulation and seed yield of sesame crops under rainfed areas. However, plant growth regulators (such as Paclobutrazol) can improve the total dry matter and seed production of the sesame crop. The effects of the paclobutrazol application on dry matter accumulation and seed yield had not been studied before in sesame under rainfed conditions. Therefore, a two-year field study during 2018 and 2019 was conducted with key objectives to assess the impacts of paclobutrazol on leaf greenness, leaf area, total dry matter production and partitioning, seed shattering, and seed yield of sesame. Two sesame cultivars (TS-5 and TS-3) were treated with four paclobutrazol concentrations (P0 = Control, P1 = 100 mg L ⁻¹ , P2 = 200 mg L ⁻¹ , P3 = 300 mg L ⁻¹ ). The experiment was executed in RCBD-factorial design with three replications. Compared with P0, treatment P3 improved the leaf greenness of sesame by 17%, 38%, and 60% at 45, 85, and 125 days after sowing, respectively. However, P3 treatment decreased the leaf area of sesame by 14% and 20% at 45 and 85 days after sowing than P0, respectively. Compared with P0, treatment P3 increased the leaf area by 46% at 125 days after sowing. On average, treatment P3 also improved the total biomass production by 21% and partitioning in roots, stems, leaves, capsules, and seeds by 23%, 19%, 23%, 22%, and 40%, respectively, in the whole growing seasons as compared to P0. Moreover, under P3 treatment, sesame attained the highest seed yield and lowest seed shattering by 27% and 30%, respectively, compared to P0. This study indicated that by applying the paclobutrazol concentration at the rate of 300 mg L ⁻¹ in sesame, the leaf greenness, leaf areas, biomass accumulation, partitioning, seed yield, and shatter resistance could be improved. Thus, the optimum paclobutrazol level could enhance the dry matter accumulation and seed production capacity of sesame by decreasing shattering losses under rainfed conditions.
 
Article
The number of areas subject to drought is likely to increase in response to climate change and will affect the yields of globally important crops such as sugarcane. In this respect, the aim of the present study was to assess the drought tolerance of sugarcane varieties in different phenophases and identify the physiological and biochemical characteristics associated with the lowest yield loss under drought conditions. Six of the most widely cultivated varieties in the region were studied, namely SP79-1011, RB855113, RB92579, RB867515, RB72454 and RB855536. Plant physiological characteristics were assessed during the dry season in the tillering, intense growth and ripening stages, and yield was quantified after 12 months of cultivation. This study shows that different sugarcane varieties are more affected by drought in the intense growth phenophase, since plants showed a greater decline in water and osmotic potential at midday during this period. The varieties most affected by drought in this phenophase were RB855536 and RB855113, which exhibited greater reductions in water and osmotic potential. They also had larger osmoregulator accumulation as a response to drought, but not enough to prevent dehydration, which likely contributed to the lower yield. The RB867515 and RB92579 varieties underwent no significant change in osmotic potential at midday during drought stress in the intense growth phase, despite of low leaf water potential, and little variation in the osmoregulators contents. For these reasons, these two varieties showed greater drought acclimation potentials and were more productive as submitted to drought conditions.
 
Bioconcentration factor (BCF) of soil Pb and Cd by land cress and spinach at different levels of soil contamination. 
Article
Soil contamination with potentially toxic elements (PTEs) in agricultural lands, in part, is responsible for limiting the crop productivity and the food chain contamination. The objective of this study were to asses the limiting of crop productivity by cadmium (Cd) and lead (Pb), the potential transfer and bioaccumulation of these PTEs in plants, and ultimately the food chain contamination to ensure that the pre-established soil threshold concentrations for Cd and Pb are enough to control food chain exposure to them. Therefore, land cress and spinach were grown in some pots containing a sandy loam soil contaminated with increasing concentrations of Pb and Cd. The concentrations of Pb and Cd in land cress and spinach at any level of soil contamination were compared with the threshold concentrations of Pb and Cd in leafy vegetables as established by the Codex Alimentarius Commission (CAC). A bioaccumulation factor was calculated to estimate the potential transfer of Pb and Cd to the food chain. According to the results, Pb was of more phytotoxicity than Cd. The lower limit of the maximum acceptable concentration of Pb in soil was safe enough to ensure the prevention of the food chain contamination to Pb. Results also showed that growing land cress on contaminated soils was of great potential risk of Pb transfer to the human food chain when compared to spinach. The pre-established maximum acceptable concentration of Cd in soil of 1-20 mg kg -1 was not safe to prevent the contamination of food chain. Cd was of a greater potential of entering the human food chain than Pb.
 
Article
A field experiment was conducted to examine the effects of different depths of nitrogen (N) fertiliser placements on N accumulation, remobilisation and NO3ˉ-N content in soil of rainfed wheat. Nitrogen was applied on the surface (D1) and in the 10 cm (D2), 20 cm (D3) and 30 cm (D4) soil layers from 2010 to 2012. Compared with D1 and D2, D3 and D4 treatments obtained significant higher N distribution amounts in grain and N accumulation amounts at maturity. D3 and D4 treatments increased the N accumulation amount of vegetative organs at anthesis and at maturity. D3 treatment resulted in significantly higher N translocation amounts from vegetative organs to grains compared with D1 and D2 treatments and had no significant difference with D4 treatment. Compared with the D1 and D2, D3 and D4 treatments obtained significant higher NO3ˉ-N contents in the 20 cm to 120 cm soil layer at anthesis from 2011 to 2012. However, D3 treatment showed no significant differences with D1 and D2 treatments at maturity in terms of the NO3ˉ-N contents in the 40 cm to 100 cm soil layer. D4 treatment produced the highest NO3ˉ-N contents in the 40 cm to 140 cm soil layer. Grain yield, N uptake efficiency, apparent N recovery efficiency, N agronomic efficiency and N partial factor productivity were significantly increased by D3 and D4 treatments. These results suggest that the D3 treatment facilitates the best wheat production and highest efficiency among all treatments. © 2015, GORGAN UNIV AGRICULTURAL SCIENCES AND NATURAL RESOURCES. All rights reserved.
 
Planting, glycinebetaine (GB) application, aflatoxin inoculation and harvesting dates for each year of the study. 
Article
Exogenously applied glycinebetaine (GB) accumulates at high levels in maize (Zea mays L.). Under water deficit and high temperature conditions GB application produces yield benefits. These sub-optimum conditions often result in high levels of aflatoxin accumulation which reduces grain quality. A 3-year (2008, 2009 and 2010) field experiment was conducted to determine the effects of GB on maize yield and aflatoxin accumulation. Weekly and alternate weekly GB application increased plant biomass by 10 and 13%, respectively. Net photosynthesis increased by 6% with GB application; however, stomatal conductance, transpiration rate and electron transport rate were not significantly affected. Grain yield increased by 6 and 13% with GB applied alternate weekly and weekly, respectively, over control plots averaged over years. GB application resulted in a trend of reduced aflatoxin accumulation in inoculated ears compared with non-inoculated controls in 2009 and 2010; however, inherent field and sampling variation did not allow us to conclude statistically any advantage attributable to GB application. We can conclude that GB did not significantly reduce aflatoxin production in the inoculated treatments.
 
Article
Wheat-cotton double cropping practices on a large scale in cotton belt of the Yellow River Valley and the Yangtze River Valley in China. Field experiments were conducted to determine the effects of wheat-cotton double cropping on cotton biomass accumulation and yield formation during 2011/12 and 2012/13 growing seasons. Two cotton cultivars, Siza 3 (mid-late maturity) and CCRI 50 (early maturity), were used in three cropping systems including monoculture cotton (MC), wheat/intercropped cotton (W/IC) and wheat/direct-seeded cotton (W/DC). Lint yield in double cropping systems were significantly lower than that in monoculture. Compared with MC for Siza 3, lint yield in W/IC and W/DC were decreased by 10.9 and 41.8%, respectively and 9.9 and 35.9% for CCRI 50, respectively. These reductions were largely ascribed to the fewer cotton bolls per unit area. Growth analysis showed that IC showed a pronounced delay in early development due to the initial shading from wheat on cotton seedlings and owing to delayed sowing, DC was easily affected by lower temperature during flowering and boll formation stage. And that consequently was delaying reproductive development, affecting cotton biomass accumulation and distribution and finally limiting crop productivity. Further, the diminished source capacity coupled with inadequate biomass production was the main determinant factor to limit lint yield in W/IC, while the reduced sink capacity with less partition to reproductive organs was the primary factor limiting lint yield in W/DC. Comparing to mid-late maturity of Siza 3, early maturity cultivar of CCRI 50 had a yield advantage in double cropping sequential system, since its shorter growing period.
 
Article
Effects of 1-aminoethoxyvinylglycine hydrochloride (AVG or Aviglycine HCl or ReTain) and alpha-naphthalene acetic acid (NAA) on fruit retention, fruit quality, eveloved ethylene, and respiration in 'Rome Beauty' and three 'Delicious' apple cultivars (Malus domestica Borkh.) were studied. The experimental trees were treated with either AVG, applied at 120 g a.i. per 935 L.ha(-1) or NAA, applied at the rate of 10 ppm at 1870 L.ha(-1). The AVG treatment was applied four weeks before anticipated harvest date while the NAA treatment was applied 7 days before harvest. In both 'Delicious' and 'Rome' apples, application of AVG maintained fruit retention and firmness but reduced starch hydrolysis, ethylene evolution, and respiration as compared to the NAA treatment. In the later harvests, fruit weights in NAA-treated trees were slightly higher than those treated with AVG. Fruit retention, maturity and quality differences between AVG and NAA treatments were more pronounced as the time past from the commercial harvest dates. Based on this study, application of AVG is more effective than NAA in preventing fruit drop and delaying fruit maturity and thus storage life of apples.
 
Germination variance analysis in embryo developmental stages and medium type.
Article
Hybrids as various resources have valuable importance in tree breeding. Today, improvement programs by using poplar and willows and their hybrids play basic role in supplying wood and decreasing pressure on natural forests. This research was carried out in order to study inter-generic hybridization possibility between Salix aegyptica and Populus caspica species from Salicaceae to achieve new hybrids. Embryo rescue technique was used in order to produce new inter-generic hybrids in salicaceae. The experiment was performed in factorial completely randomized design with 3 replication in embryo developmental stages and different media treatments. The analysis of data showed that inter-generic cross ability between Salix aegyptica and Populus caspica was possible and 14 day after pollination and MS medium containing 3 percent sucrose were the best time and medium for obtaining high amount of germinated hybrids.
 
Article
Global climate change escalates the rise of atmospheric CO2 concentration and temperature, which impact crop production in agricultural ecosystems. As the second important macronutrient, phosphorus (P) fundamentally mediates the crop adaptability to climate change. An overview on previous work on crop P acquisition and soil P dynamics in responses to elevated CO2 and temperature would be critical for further advancing our knowledge on P cycling under climate change and its management to maintain agroecosystem sustainability. This review focuses on the effects of elevated CO2 and temperature on root morphology, root exudation, and associated biochemical properties in the rhizosphere in relevant to crop P acquisition and soil P availability. Studies indicate that elevated CO2 and temperature could increase P uptake of crops, such as rice and soybean when crops are grown within the range of optimal growth temperature. Elevated CO2 and temperature not only alter root exudates and changes the activity of soil enzymes and microbes the in rhizosphere environment, but also directly influence soil chemical and biochemical processes and thus the bioavailability of P. It is worth to focus on P-solubilizing microbial community composition, and microbial function on soil P mobilization in the rhizosphere of crops grown under climate change.
 
Per cent contribution to total plant biomass accumulation by different plant parts at 50% flowering (50%F) and physiological maturity (PM) relative to N fertilization in sunflower.  
Components of nitrogen use efficiency.
Plant partitioning and dry matter accumulation in relation to N fertilization (across tested hybrids) at (a) 50% flowering and (b) physiological maturity of sunflower [Bars within same group (biomass accumulation by) sharing the same letters do not differ significantly (DMRT, significance level= 0.05); values in parentheses indicate ± s.d.; DMA: dry matter accumulation.  
Effect of N fertilization rates (across hybrids) on seed yield (pri-axis), N uptake and use efficiency (sec-axis) in sunflower. Bars and lines sharing the same lower case letter do not differ significantly (DMRT, p-value<0.0001, within treatment comparison).
Seed yield response of sunflower hybrids to N fertilization with chlorophyll content (SPAD values)/LAI.
Article
A field experiment was conducted to study the effects of N fertilization on uptake, accumulation/remobilization, use efficiency and yield of sunflower grown in alluvial plains of northwestern India comprising four hybrids (PSH 996, PAC 3789, PSH 569 and SH 3322) and five N levels (Control, 40, 80, 100 and 120 kg N ha-1) in split-plot design with three replications. Increased N fertilizer rates significantly prompted sunflower yield only up to 100 kg N ha-1. Every additional kilogram of N taken up increased sunflower yield by 26 kg ha-1. Significant genetic variation for seed yield and NUE traits explicated PSH 569 as the efficient one at sub-optimal N application while PSH 996 outperformed others at N80, N100 and N120. Dry matter accumulation pattern revealed average harvest index of 30% with 29% of the biomass as stalk, 19% as leaf and 22% as thalamus. Temporal changes in N acquisition indicated most of the total N uptake upto 50% flowering while maximum remobilization takes place during reproductive phase. Significant correlation between N uptake and N use efficiency parameters with yield indicate the importance of N nutrition in sunflower; LAI (r=0.841**), N uptake (r=0.956**), NUpE (r= -0.814**), NUtE (r= -0.787**), NUE (r=-0.802**). Variation in NUE was more closely associated with NUpE (r=0.996**) than NUtE (r=0.812**) and linearly decreased with increasing leaf greenness (R2=0.70) and total leaf area (R2=0.81). This work will complement other studies to establish a baseline for breeding N efficient sunflower genotypes be grown under semi-arid tropical conditions in India and similar environments. © 2016, GORGAN UNIV AGRICULTURAL SCIENCES AND NATURAL RESOURCES. All rights reserved.
 
Article
The Loess Plateau is among the major winter wheat (Triticum aestivum L.) production areas of China. However, wheat production is uncertain across the Loess Plateau, and its potential for yield improvement remains unknown. In the present study, we divided winter wheat growing areas on the Loess Plateau into four climatic zones: arid (zone I), semi-arid (zone II), semi-humid (zone III), and humid (zone IV). Then, we used the validated Agricultural Production Systems Simulator (APSIM) to model Yp (potential yield) and attainable yield (water-limited yield, Yw; nitrogen-limited yield, Yn) of winter wheat on the Loess Plateau from 1961 to 2016. The simulated means for weighted Yp, Yw, and Yn were 8.87, 6.49, and 5.42 t ha–1, respectively. Ya reached only 57% of Yp, which represents the amount of room available for yield improvement. Across the Loess Plateau, the yield gap caused by water limited (YGw) and nitrogen restricted (YGn) were 27% and 39% of potential wheat production. The difference between YGw (3.54 t ha–1) and YGn (3.87 t ha–1) was not significant in the semi-arid climate (zone II), due to low precipitation rates. Compared with irrigation, nitrogen deficiency was the key factor causing the winter wheat yield gap. However, the yield gap caused by nitrogen restriction varies regionally. Irrigation in arid (zone I) was more important than in the other climates, whereas these climate regions required nitrogen more pressing. Areas with a large potential for increased winter wheat yield on the Loess Plateau were mainly distributed in the semi-arid climate (zone II).
 
Article
Rice phenology was determined by temperature and agronomic management. It was essential to quantify the interaction between warming temperatures and rice phenology to understand the impact of climate change in rice farming systems. Based on the quantitative analysis of data from double-cropping rice in the south of China in the last 20 years, we found that the average temperature of the whole growth periods of early rice and late rice increased by an average of 0.76 °C and 0.49 °C decade⁻¹, respectively. The whole growth period (WGP) change trend of early rice decreased by 0.07 d decade⁻¹, but the WGP of late rice increased 1.26 d decade⁻¹. The vegetative growth period (VGP) and the reproductive growth period (RGP) of early rice and late rice were all shorted. Regression analysis showed that the VGP of early rice and late rice decreased by 2.99 days and 2.82 days, and the RGP decreased by 1.67 days and 1.81 days, respectively, as the mean air temperature increased by 1 °C during the corresponding stages. The WGPs of early rice and late rice decreased by 3.81 days and 5.31 days, respectively, with the mean air temperature increased by 1 °C during growth duration. According to our studies, the rising mean air temperature could lead to a shortening of the double-rice growth period. Therefore, we must adjust the planting pattern of the double-rice system to mitigate and adapt to future climate change.
 
Article
The objective of the paper was to illustrate using and usefulness of a joint AMMI and cluster analyses to assess the grain yield adaptive response of Polish and foreign 31 winter wheat cultivars in a range of 20 environments (locations) and across 3 years (2005-2007) under integrated crop management, using data obtained in the post-registration variety testing trials (called PDO trials), to identify those entries with specific and wide adaptation. Two-stage combined analysis of variance for data in the three-way GLY classification was carried out according to a mixed model (cultivar and location as fixed factors and years as random factor). GL repeated (across years) interaction effects were modeled by (a) joint regression and (b) additive main effects and multiplicative interaction (AMMI). The thirty one cultivar adaptive responses, expressed by nominal yields based on significant AMMI-1 model, accounting for 27.8% of SS for GL interactions, were divided into six homogenous groups by Ward's method of cluster analysis. Group-mean cultivar adaptive responses indicated clearly the wide adaptation of cultivars in groups 1 and 2 including mostly German and United Kingdom entries and also two Polish ones. Cultivars from group 6, including three Polish cultivars and three foreign ones, were among at most four top-ranking entries at all locations excluding one environment (Wyczechy at Pomerania region). Cultivars from group 3, including seven Polish cultivars and one from United Kingdom and France, showed extremely specific adaptation characterized by nominal yield responses being positively related to GL interaction PC 1 scores of the locations. However, cultivars from group 5, including five Polish ones and a French one were poor adapted to the growing area. Presented the joint AMMI and cluster analyses were effective to distinguish adaptive responses of studied cultivars on the basis of data from PDO trials and could be seen as a better alternative, based more on probability-approached methodology, to common pattern analysis.
 
Article
To evaluate the effects of planting methods and deficit irrigation, an experiment was conducted on treatments of direct seeding with full irrigation (DSI1), transplanting on Nov. 1 with full irrigation (T1I2), direct seeding with omitting one irrigation at rosette stage (DSI3), direct seeding with omitting two irrigations at rosette stage (DSI4), direct seeding with omitting irrigation after rosette and before flowering stage (DSI5), direct seeding with omitting irrigation from the grain filling stage to physiological maturity (DSI6) and transplanting on Oct. 9 with full irrigation (T2I7) on yield, water productivity and actual crop evapotranspiration of canola cultivars (Neptune and Danube), at the research station of School of Agriculture, Shiraz University, Shiraz, Islamic Republic of Iran, in the two consecutive growing seasons (2015–2017). This study was carried out as a factorial experiment based on complete randomized block design with four replicates. In this study the AquaCrop model was used for estimating root depth and actual crop evapotranspiration. The results showed that planting methods had significant effect on the grain and oil yields. It was also revealed transplanting on Nov. 1 was not a suitable date for transplanting. Water productivity for grain and oil yields was calculated based on irrigation water and actual crop evapotranspiration. The lowest water productivity was obtained 0.03 kg m⁻³ based on actual crop evapotranspiration in the second year for oil yield in the T1I2 treatment. Also, the results indicated that in the direct seeding treatments DSI6 treatment and in cultivars, Neptune had the lowest grain and oil yields.
 
Article
Himalayas, are among the areas most vulnerable to global warming, however, little is known about warming impacts on the crops. Therefore, the actual affects of anticipated warming on winter wheat were tested in Tibet, China. During the period 1988-2012, Tibet region has experienced a large increase in daily mean, minimum and maximum temperatures during wheat growing seasons by 0.50, 0.67 and 0.51 °C every ten years, respectively. The de-trended wheat yield increased by 34.4 kg ha-1 year-1 during this period. According to the historical data, 1 °C increase in daily mean temperature could get 370.6 kg ha−1 gain in wheat yield. Similar gains in wheat yield were found in a field warming experiment with an increase of 1.1 °C in daily mean temperature. The field warming caused a significant reduction in the pre-anthesis phase and entire growth period by 14 and 13 days, respectively. The green leaf areas and spike number in the warmed plots were significantly higher than that in non-warmed plots, while the grain number per spike was significantly lower in the former than the later (P<0.05). The main mechanism underlying the positive affects of this moderate warming on wheat yield is through improving plant development and growth during the pre-anthesis phase by mitigating the low temperature limitation. This study suggests that further efforts should be directed towards the improvement on agriculture infrastructure to utilize the positive affects of climatic warming on crop production. © 2016, GORGAN UNIV AGRICULTURAL SCIENCES AND NATURAL RESOURCES. All rights reserved.
 
Article
Sugarcane (Saccharum officinarum L.) yield is affected by climate, soil and management. The main approach used in Brazil defines the suitable area for growth considering soil and climate data, without considering the capacity of local management in reducing yield-limiting factors. Thus, the aim of this study is to characterize homogenous areas using sugarcane actual yield, climate, total plant-available soil water capacity (TASW), and production intensity data. The study was conducted in the Goiás state, totalizing 246 counties. The first step was to group areas based on actual yield obtained from 1973 to 2016. The groups were characterized considering climate (rainfall and air temperature), soil (TASW), and sugarcane production data. Actual sugarcane yield formed eight homogenous groups, numbered 1–8, containing 12 and 50 counties each group. The counties groups with a higher yield have a higher production intensity. They are near mills, have a higher TASW, and are divided in traditional and recent expansion areas. The counties groups with a lower yield have a lower TASW and a higher air temperature. Hotter regions are in the western and northern state border. New areas of expansion were available near current sugarcane mills within areas with a higher TASW. Thus, preferential regions were defined by associating edaphoclimatic conditions with high yield. These areas can receive support to improve sugarcane production.
 
Article
Water management technologies under projected climate change will play key role in sustainable rice production. Modeling approach was used to assess the impact of climate change on rice production under drip irrigation (DIR) and conventional puddle transplanted (PTR) in subtropical India. The genotype coefficients of CERES-Rice model (cv. Naveen) were determined and tested using experimental data for the years 2012–2014. Close match between the observed and simulated values was recorded during both the years which led to higher d-index (> 0.95) and lower normalized RMSE (RMSEn) values. Under the projected climate change scenarios (RCP 4.5 and RCP 8.5), grain yield reduced over the period 2020–2080, with higher decline in RCP 8.5. Over the period, higher nitrogen (N) use efficiency in DIR led to lower yield reduction over PTR. Among the different adaptation measures, higher fertilizer N dose was able to mitigate negative impact of temperature rise up to 3.3 °C over base period, beyond which grain yield was significantly reduced. Results of the simulations for the different sowing dates stated higher reduction in grain yield with delayed sowing in DIR as well as in PTR for both (RCP 4.5 and 8.5) climate change scenarios. However, early sowing resulted in better crop establishment in DIR leading to better yield compared to PTR in both the climate change scenarios.
 
Article
Underutilised grain legumes are being promoted as part of crop diversification efforts. However, the lack of comparable information to major legumes is limiting these efforts. The first benchmarking study to compare development and productivity of selected underutilised [bambara groundnut (Vigna subterranea) and cowpea (Vigna inguiculata) and major [groundnut (Arachis hypogaea) and common bean (Phaseolus vulgaris)] grain legumes under varying environments was conducted in KwaZulu-Natal, South Africa during 2015/16 and 2016/17. A completely randomised block design with three replications was used at all sites. Crop phenology, yield, water use (ET) and water productivity (WP) were determined for the crops. Data were analysed separately using ANOVA. Biplot analysis was done using GGE. Bambara groundnut was slow to emerge across sites and seasons (> 211 degree days). Common bean was early maturing (< 1677 degree days) while groundnut and bambara groundnut were late maturing (> 1699 degree days). Yield varied significantly (P < 0.05) across environments and seasons. For all environments, common bean had the lowest ET (208–313 mm); bambara groundnut had the highest ET (437 mm), which was recorded during 2015/16. The highest and lowest WP (0.98 and 0.12 kg m⁻³, respectively) were observed for groundnut. Cowpea had the most stable WP (0.28–0.38 kg m⁻³). Based on mean values, the major legumes out-yielded the underutilised grain legumes. Crops behaved differently across different environments. The potential of bambara groundnut was limited to sandy soils. There is need for investments in improving yield of underutilised grain legumes to make them more attractive for crop diversification.
 
Article
Environmental stresses such as high temperature and drought due to climate change are strongly impacting crop production, including wheat. In this study, Statistical Downscaling Model (SDSM) was used under three Representative Concentration Pathways (RCP) scenarios (RCP2.6, RCP4.5, and RCP8.5) from 2015 up to 2100; the purpose was to know any possible climate changes at the Sanandaj (3525ʹ, 47° 00ʹ) and Qorveh (35° 16ʹ, 47° 79ʹ) locations. Prediction of the flowering date, maturity date, grain-filling period, and potential yield of winter wheat during the studied period were carried out by using the LINTUL model. Then, seven possible sowing dates (from September 27 to November 27) were examined as a strategy for adoptation to the effects of future climate change and also possible changes of the developmental stages and evaluation of final grain yield of winter wheat under all the three RCP scenarios. The findings indicated that the maximum and minimum temperatures tend to increase at both locations under the RCP4.5 and RCP8.5 scenarios. In general, change in flowering date will not be significant, particularly at the Sanandaj location, but the maturity date will be earlier than current dates at both stations under all three scenarios. There will be a slight decrease in the grain-filling period, particularly at the Sanandaj location. The total decline in the grain-filling period for the Sanandaj station would be about 1.35, 1.7, and 3.8 days by the year 2100 for the RCP2.6, RCP4.5, and RCP8.5 scenarios, respectively. The average winter wheat yield changes for the 2015–2100 period would be about − 88.8, − 201.9, and − 364.9 kg ha−1 at the Sanandaj location and 222.7, − 135.15, and − 348.5 kg ha−1 at the Qorveh location, under the RCP2.6, RCP4.5, and RCP8.5 scenarios, respectively. Finally, it is found that earlier sowing dates would lead to earlier flowering and maturity dates. At Sanandaj and Qorveh stations, bringing sowing date forward from the current dates (October 27) to September 27 (first possible sowing date) would increase yield by 26 and 12 percent, and its delay to November 27 (the latest possible sowing date) would decrease yield by 19 and 11 percent, respectively. It seems that the expedition of the sowing date in the Mediterranean-type environment can act as a reliable strategy in response to future climate changes. Shifting the sowing date causes the grain-filling period to be less exposed to high temperatures and drought stress in late spring, which may results in even higher wheat yield.
 
Article
India is the second largest producer of potato in the world. The Indo-Gangetic plains (IGP) is the main potato growing region accounting for almost 85% of the 1.8 Mha under the crop in India where it is grown as an irrigated crop during the winter season. Since IGP is in sub-tropical plains, duration of the thermally suitable window is the main determinant limiting yields. Hence the impact of climate change on potato in the IGP was assessed using MIROC HI.3.2 A1b and B1, PRECIS A1b, A2, B2 scenarios and estimated the potential adaptation gains. The potato crop duration in the IGP is projected to decrease due to climate change. The evapotranspiration (ET) is projected to increase while the water use efficiency (WUE) for potato yield is projected to decline in future climates as a consequence of low threshold temperatures for decline in WUE and yield than the ET. Results indicate that the upper threshold for ET decrease is ~23 °C while that for WUE is 15 °C. The optimal temperatures for tuber yield is ~17 °C and thus the reduction in WUE in future climates is discernable. Climate change is projected to reduce potato yields by ~2.5, ~6 and ~11% in the IGP region in 2020 (2010-2039), 2050 (2040-2069) and 2080 (2070-2099) time periods. Change in planting time is the single most important adaptation option which may lead to yield gains by ~6% in 2020 and its combination with improved variety or additional nitrogen may be required to adapt to climate change leading to positive gains by ~8% in 2020 and by ~5% even in 2050. However, in 2080 adoption of all the three adaptation strategies may be needed for positive gains. Intra-regional differences in the impact of climate change and adaptation gains are projected; positive impact in northwestern IGP, gains in Central IGP with adaptation and yield loss in eastern IGP even with adaptation.
 
Article
Limited arable land area and deteriorating soil health in smallholder farmers’ fields of subtropical regions in China have led to an urgent demand for sustainable production practices with greater land productivity and nutrients use efficiency. A group of field experiments at three locations (Yaan, Lezhi and Renshou) in two consecutive years of 2012–2013 were conducted to study crop production and nutrients recovery of maize (Zea mays L.) and soybean (Glycine max (L.) Merr.) in monocropping and additive relay intercropping systems. The results showed that the total crop yields of the 2:2 maize-to-soybean wide-narrow row spacing planting pattern (RIwn) were significantly higher than that of the 1:1 maize-to-soybean equal row spacing planting pattern (RIe), and the average land equivalent ratios (LER) of the grain yield were 1.79 and 1.49 for the RIwn and RIe, respectively. The nitrogen (N), phosphorus (P) and potassium (K) recovery efficiency calculated by the ratios of crop nutrients removed and fertilizer input indicated that the RIwn had a higher nutrients recovery than the RIe due to proper spacing between maize and soybean rows and higher soybean yield in RIwn. In terms of the amount of fertilizer applied, based on this experiment, P should be reduced in maize plantings and increased in soybean plantings to maintain the balance of soil P. Considering the higher temperatures during the soybean vegetative growth phase, N fertilizer inputs should be controlled to prevent excessive soybean growth. In addition, excess K was taken up in the crop biomass, maybe the straw should be returned to the field to maintain soil K fertility sustainable for the long term.
 
Article
Water deficit is the most limiting factor for seed yield of crop species in the arid and semi-arid regions. Due to increasing limitation of fresh water resources and importance of safflower (Carthamus tinctorius L.) as a significant oilseed crop in Iran, it is necessary to evaluate physiological responses of drought tolerance and its association with seed yield of this crop in water stress condition. In this study, 21 safflower genotypes were planted by hand in the field under water stress and non-stress conditions in a randomized complete block design with two replications during 2 years (2016–17). The results indicated that water deficit stress significantly reduced relative water content (RWC), chlorophyll a (Chl-a) and chlorophyll b (Chl-b) concentrations and seed yield, but increased ascorbate peroxidase (APX) and peroxidase (POX) activities and leaf proline concentration. Significant differences were observed among the genotypes for all studied traits except Chl-b concentration. Genotypes were discriminated according to their response to drought using stress tolerance index (STI). Drought tolerant genotypes displayed a higher capability for accumulation of proline in association with maintaining RWC, antioxidant enzymes activity and higher seed yield, compared to the drought sensitive genotypes. Presented results suggested that safflower genotypes with higher levels of antioxidant enzymes activity, RWC and proline accumulation are characterized by a higher STI. Therefore, these physiological traits can be employed as effective criteria for selecting safflower genotypes with more tolerance to water deficit stress.
 
Article
Under the pressure of competitiveness and climate change, the rice sector has adopted multiple agricultural technologies to improve productivity, reduce production costs, and be environment-friendly. The Massive technology adoption program (AMTEC) is an example of Colombian rice production. Although all components of AMTEC have been approved to improve the rice yield in demo farms, these impacts, along with other factors under actual farm conditions, are unclear. Data were obtained from the 2016 National Rice Census data of 20,174 rice production units. This study determines the effects of each AMTEC technology and other agricultural factors on paddy rice yield under actual farm conditions using the multiple regression analysis with a backward stepwise method. The average paddy rice yield was 5.508 t ha−1 with a considerable variation across the whole country (0.110–12.187 t ha−1). The results showed that 69.47% of the variation in paddy rice yield was influenced by rice cultivation regions, farm size, technical assistance, applying chisel plow, having a ban, having an irrigation system, and the number of nitrogen fertilizer applications. Landplane, certified seeds, and drill sowing were the three components of the AMTEC program that contributed to an increase in rice yield. Notably, the paddy rice yield was 0.361 t ha−1 with an additional N fertilizer application or the farm under the irrigation system. It also increased from 0.404 to 0.362 t ha−1 for the farm that used drill sowing compared to the farm that used benchmark technologies. The results also showed that the farm that received technical assistance had a 0.150 t ha−1 compared to their counterparts who did not, and there was a significant difference among its sources. Therefore, to improve the rice yield, the above-mentioned multiple technologies should be widely disseminated. Additionally, the farms should receive technical assistance, particularly from private companies such as supply distributors or milling companies.
 
Article
Dwindling water resources appear to become a great challenge threatening the future of sustainable rice cultivation as it consumes substantial amount of water available in agricultural farming par se. Ostensibly being a water-guzzling crop, aerobic rice could be a viable option requiring less irrigation water than conventional farming, instead. However, grain yield penalty while grown continuously is becoming a strong demerit for sustainable aerobic rice cultivation. A better understanding of the causes and concerns vis-à-vis alleviation mechanism suggested a long term field experiment studying rotational sequences with different non-rice crops in a system perspective mode. Thus, the current field study was conducted for consecutive five years exploring the potentiality of aerobic rice based crop rotations with maize, ground nut and green gram in view of promoting soil health resiliency for arresting grain yield decline during 2013–14 to 2017–18. The study revealed a perceptible depletion in soil quality parameters at the end of last year/5th year accounting around 2.70% soil organic carbon, 1.70% available nitrogen, 1.60% available phosphorus, 1.39% available potassium, 2.75% iron and 1.35% zinc as compared those in the 1st year of the study. Even the situations also aggravated root nematode populations, especially rice root knot (Meloidogyne graminicola) and root rot nematode (Hirschmanniella oryzae) that inhibited usual root growth pronouncing less volume (26.50 cc plant−1) and density (0.54 g cc−1). As a result, drastic depression in usual growth and development of continuously grown aerobic rice caused more than 50% grain yield (2.04 t ha−1) decline at the 5th year compared to that (4.30 t ha−1) at the initial 1st year. However, no detrimental impacts were visualized on rice while grown in yearly rotation with non-rice crops; instead, grain yield increased significantly, especially in rotation with groundnut or green gram (4.40–4.46 t ha−1). Additionally, rice grain protein content (6.92–7.0%) also enhanced as compared that (6.36%) at pure aerobic rice stands. Thus, implication of this current study could have far reaching consequences ensuring aerobic rice cultivation sustainable in a rotational sequence with ground nut/green gram even under the apprehension of irrigation water deficiency.
 
Article
The cultivation of aerobic rice appears to be a potential option while mitigating threats of looming water scarcity for sustainable rice production. Although, severe prevalence of multi-flush weed pressure inhibiting nitrogen utilization for optimum grain yield becomes the crux of the problem for up-scaling this technology. Thus, the hypothesis of the study was that critical period of weed control (CPWC) governs nitrogen accumulation in aerobic soil—plant continuum, which appears to be the major determinant of ultimate grain yield in aerobic rice cultivation. With this view, the field studies were successively conducted in two locations at Panthnagar, Uttar Pradesh during 2015 and at Cuttack, Odisha during 2016 in India. Nitrogen utilization was estimated with varying magnitude of critical period of weed prevalence at 15 days interval since sowing till 75 days of crop growth. Results recorded significantly higher nitrogen uptakes of 106.6 and 106.0 kg ha−1 while maintaining near weed-free situations during initial 75 days of crop growth at Panthnagar and Cuttack respectively, which were however comparable with similar situations maintained also at 60 and 45 days of crop growth in respective location. Consequently, stands at these situations produced comparable grain yield of 5.56 and 5.25 t ha−1, 5.40 and 5.00 t ha−1, and 5.15 and 4.70 t ha−1 at corresponding locations, which were significantly higher than those corresponding weedy stands producing 1.35 and 0.90 t ha−1, 1.48 and 1.10 t ha−1, and 2.86 and 2.45 t ha−1 grain yields in respective locations. Thus, higher nitrogen gains of 0.42 and 0.06%, and 0.31 and 0.03% were attributed to initial 75 and 60 days weed-free stands respectively at Panthnagar and Cuttack. While, nitrogen losses were maximum of 24.99 and 25.69%, and 24.26 and 24.85% at corresponding weedy crop stands; although, initial 15 day’s weedy crop stands or initial 45 days weed-free stands recorded the lowest nitrogen losses of 0.64 and 1.35%, and 1.51 and 2.16%, instead. Therefore, the study contributed above novel information explaining the dynamic correlation of nitrogen balance with prevalence and also magnitude of CPWC where N uptake culminated at 45 days weed-free situation ensuring optimum aerobic rice productivity.
 
Article
Wheat (Triticum aestivum L.) variety mixtures represent a relatively unexplored avenue for maintaining yield and improving flour quality. A field experiment was conducted to examine the responses of three spring wheat varieties in pure variety and in variety mixtures under continuous cropping in Northeast China. Three modern spring wheat varieties, along with a three-variety mixture and a two-variety mixture of equal proportions, were planted during the growing seasons of 2006 to 2009. The mixtures were chosen mainly to have complementary traits of yield potential and grain quality. Wheat yield was not affected by continuous cropping but by growing conditions, varieties and variety mixture. Yield stability of 3-variety mixture exceeded that of the pure varieties. The 3-variety mixture consistently out-yielded the means of the respective components (mid-components), with a mean advantage of 0.17 t ha-1 over the different growing conditions. Variety mixture offers greater yield advantages over lower-yield but good-quality variety and improves dough rheological properties and some chemical properties over the higher-yield variety. The 1:1:1 variety mixtures have greater environmental plasticity and potential application in improving flour quality than pure varieties and are therefore recommended for use to Northeast China's wheat growers even in the absence of severe disease.
 
Characteristics of the analyzed cultivars of Triticum aestivum L. and Triticum spelta L. 
Relationship between SPAD measured in GS 17 (upper left), GS 25 (upper right), GS 35 (down left) and GS 41 and yield. 
Direct and indirect path coefficients in determination of grain yield of spelt and common wheats. 
Means for morphological traits and yield components of wheat cultivars in sowing terms and years of study. 
Means for yield of grains and straw and harvest index of wheat cultivars in sowing terms and years of study. 
Article
One of the goals of organic crop production is to grow species which combine traditional pro-healthy properties, innovative cultivation practices and harmony with the environment. Among the ancient species the spring spelt is especially predisposed for organic farming. In comparison with common wheat spring spelt has a relatively short research history on physiological analysis of growth and development. The objective of this study has been to compare the agronomic performance and growth characteristics of spring varieties of Triticum spelta L. and Triticum aestivum L. cultivated in the organic farming system and sown on different dates. The basis for the research were data from field plot experiments arranged in completely randomized blocks carried out in 2010 and 2011. The factors were cultivars: two cultivars of T. aestivum (Trappe, Waluta) and two cultivars of T. spelta (Roter Sommerkolben, Speltz aus Tzaribrod) and sowing terms: optimal and postponed by two weeks. During the seasons there were assessed: weed infestation and disease resistance, leaf chlorophyll index, biometric measurements associated with plant morphology and yielding and nutritional value of grains. It was stated that cultivars of T. spelta are more tolerant to unfavorable environmental conditions than cultivars of T. aestivum, showing better adaptability to habitat conditions, when-due to the worse weather-the uptake of nutrients from soil can be limited, stronger competitiveness against weeds and higher tolerance to diseases of leaves and stems. The content of chlorophyll in spelt wheat grown inorganic cultivation as well as yields are very stable across years. Under unfavourable weather conditions during the season, spelt wheat can give yields which compare to yields of common wheat, but when in the favorable weather conditions common wheat varieties generate yields higher by 42% (cv. Trappe) up to 47% (cv. Waluta). © 2015, GORGAN UNIV AGRICULTURAL SCIENCES AND NATURAL RESOURCES. All rights reserved.
 
Article
Arid and semi-arid regions in the world that produce wheat (Triticum aestivum) are faced with frequent droughts in recent years. Moreover, wheat production is highly dependent on irrigation and it is essential to increase irrigation water productivity in these regions. Therefore, the aim of this study was to investigate the effects of irrigation methods, planting methods, and nitrogen application rates on yield, water and nitrogen use efficiencies of winter wheat. The experiment arranged in split–split plot with randomized blocks with two surface irrigation methods [ordinary furrow irrigation (OFI) and variable alternate furrow irrigation (VAFI)] as the main plots, two planting methods [on-ridge planting (ORP) and in-furrow planting] as the sub plots, and three nitrogen application rates (N0 = 0, N1 = 150 and N2 = 300 kg N ha⁻¹) as the sub–sub plot. Results indicated that VAFI reduced the winter wheat grain yield, dry matter, grain number per spike, and harvest index as 12, 9, 3, and 4%, respectively; however, these reductions were not significant in comparison with OFI method with a reduction of 33% in irrigation water; as a consequence, the straw nitrogen concentration, grain protein concentration, and also water use efficiencies (WUE), irrigation water productivity (IWP), economic irrigation water productivity (EIWP) and nitrogen use efficiency (NUE) were improved in VAFI as 14, 5, 6, 26, 25, and 8%, respectively. In spite of a slight reduction in grain yield, VAFI method increased EIWP. Economic nitrogen productivity decreased about 50% by increase in N rate, and 150 kg N ha⁻¹ was the optimum rate to apply. Furthermore, VAFI decreased the seasonal ET, thereby improved WUE and IWP. In-furrow planting increased significantly the WUES while it did not enhance significantly WUE for grain. Generally, increasing the nitrogen rate increased the grain yield; whereas, there was no significant difference between the treatments of 150 and 300 kg N ha⁻¹. Results suggest that application of 150 kg N ha⁻¹ combined with in-furrow planting method and variable alternate furrow irrigation is an effective way to improve WUE, yield, yield components and NUE for winter wheat in the study area.
 
Article
Genotype × environment (G×E) interaction complicates the identification of superior genotypes. An understanding its causes is needed for a more effective breeding strategy. The objective of this study was to determine the plant traits that cause genotype × location (G×L) interaction for pod yield in peanut using a modeling approach. The CSM-CROPGRO-Peanut model was used to simulate pod yield for 17 peanut genotypes for 14 locations representative of all peanut production areas in Thailand using 30 years of historical weather data. Sensitivity analysis was used to determine the effects of individual and combinations of plant traits on pod yield and yield response to environments by varying the value of one or more cultivar coefficients and then evaluating their effects. The results showed that the cultivar coefficients that showed major effects were the duration from first seed to physiological maturity (SDPM), maximum leaf photosynthesis rate (LFMAX), the maximum fraction of daily growth that is partitioned to seed and shell (XFRT), single seed filling duration (SFDUR) and the duration of pod addition (PODUR). Those having minor effects were the duration from emergence to first flower (EMFL), maximum leaf size (SIZLF) and maximum seed weight (WTPSD). The cultivar coefficients that caused the differences in both mean yield and yield response to locations between peanut genotypes in different pairs included LFMAX, XFRT, SDPM, SFDUR and PODUR, but the causal characters differed among pairs of genotypes. It was concluded that changing the degree of genotypic response to environments is possible through selection for a combination of some of these traits, and that model simulation could be used to identify those traits.
 
Article
The effect of agronomic practices in soybean grain composition lacks information. In addition, the importance of protein and oil contents in soybean grains is increasing due to the industry demand for grain quality. It is well known that soybean grain weight can change according to environmental conditions, like different sowing dates, however, the consequences in grain composition need to be better understood. The aim of this study was to evaluate the composition, oil and protein yield of soybean grains, in response to different sowing dates (early, mid, and late), seeding rates (15, 25, 35, and 45 seeds m⁻²), and two growing seasons. Late sowing reduced grain oil content, soybean oil yield, and protein yield. The increase in seeding rate from 15 to 45 seeds m⁻² increased grain protein content from 33.8% to 35.1%, oil yield increased 10% and protein yield, 17%. The results of this study show that in the management of soybean crops the sowing date and seeding rate can change grain composition. This information demonstrates that agronomic practices should be considered by growers and breeders when considering soybean grain quality.
 
Article
The water resource shortage in North China Plain is an increasing threat to the sustainability of wheat (Triticum aestivum L.) production. A two-year field experiment was conducted to examine the effects of two supplemental irrigation (SI) methods on wheat flag leaf senescence, chlorophyll fluorescence and grain yield. The following field treatments were conducted: no irrigation (W0); SI with 60 mm of water at jointing and anthesis stages (local quota SI, Wck); SI based on the relative soil water content (SWC) of 0–40 cm soil layers with 65% field capacity (FC) at jointing stage and 70% FC at anthesis stage (W1); SI based on SWC of same soil layers with 70% FC at the jointing and anthesis stage (W2); and SI based on the SWC of same soil layers with 75% FC at jointing stage and 70% FC at anthesis stage (W3). Results showed that W0 accelerated flag leaf senescence and had reduced grain yield. Among irrigation treatments, W2 (and W3 in 2013-2014) significantly increased flag leaf water potential from 7 to 28 days after anthesis (DAA) compared with Wck and W1. Superoxide dismutase activity, catalase activity of W2 increased by 15.41% and 14.96% compared with those in Wck, resulting in the significantly decreased concentration of malondialdehyde and increased concentration of soluble protein at 14–28 DAA. The Fv/Fm at 21–28 DAA and the ΦPSII, qP and NPQ at 14–28 DAA for W2 (and W3 in 2013–2014) were also significantly higher than those of Wck and W1. Eventually, grain yield, water use efficiency and irrigation benefit of W2 were 8704.54 kg ha⁻¹, 20.86 kg ha⁻¹ mm⁻¹ and 31.44 kg ha⁻¹ mm⁻¹, respectively, which were the highest among those of all the treatments. These values increased by 5.82%, 9.65% and 6.00%, respectively, relative to those of Wck. In conclusion, the SI based on 0–40 cm soil layer and use of an appropriate relative SWC (both 70% FC at the jointing and anthesis stages) can reduce irrigation amount, delay leaf senescence and improve grain yield and water use efficiency. © 2017, GORGAN UNIV AGRICULTURAL SCIENCES AND NATURAL RESOURCES. All rights reserved.
 
Article
Sowing of bacterial inoculated seeds and using different cultivar-specific row spacing are 2 well-known agricultural practices in soybean production. However, the connection between different bacterial seed inoculations and row spacing has not previously been investigated in a single study. A 3-year field experiment (2015–2017) was carried out on soybean cv. ES Mentor to assess the effect of 4 rhizobia inoculation treatments (un-inoculated control, C; factory-inoculated seed, F; fresh pre-sowing seed treatment with commercial inoculant, I; and a combination of treatments F and I, FI) and 3 row spacings (12.5 cm, 25 cm and 37.5 cm) on the protein, oil, crude fibre and ash content. The seed, protein and oil yields were determined as well as a thousand seed weight, plant height, pod number and harvest index. There was no interaction between plant spacing and inoculation; however, the inoculation treatments enhanced protein content of seeds by 1.2–1.7%, and increased yields of seed, protein and oil by a maximum of 6.8%, 8.3% and 5.9%, respectively, compared to the un-inoculated control, which produced an average seed yield of 4098 kg/ha. The inoculation treatments also had a moderate influence on biometric measurements. Row spacing had a pronounced effect on seed, protein and oil yields, with plants in 12.5 cm and 25 cm row spacings generating higher yields than those in 37.5 cm row spacings. Correlation analysis showed a significant positive association between seed yield and pod number, and a significant negative correlation between protein and oil content.
 
Article
Safflower (Carthamustinctorius L.) is an oilseed crop adapted to drought prone arid and semi-arid environments. This study was conducted to evaluate the effects of water deficit stress on antioxidant activity, membrane stability index (MSI), leaf chlorophyll content, leaf area index (LAI) and their relationship with seed yield using 64 safflower genotypes grown under normal and water deficit stress field condition. Plants were grown under normal irrigation until branching growth stage when water deficit stress was applied to the plants. Analysis of variance showed the significant effects of genotype, water deficit and their interactions on the physiological traits that examined. Water deficit stress significantly decreased leaf area index, leaf chlorophyll content and the membrane stability index means over all 64 genotypes whereas it caused significant increase in antioxidant compounds (APX and POX). The results also revealed the positive and significant correlations between antioxidant enzyme activities with seed yield under water deficit conditions. The stress susceptibility index (SSI) identified water-deficit tolerant genotypes (Kordestan 3 and C411) that did have outstanding yield performance per se in stress environments.
 
Article
This study was conducted to determine whether selecting an optimum sowing date could improve yield. The experiment consisted of sowing a film-covered, drip-irrigated cotton field on four sowing dates from April to May in 2011-2012 at the Agrometeorological Experimental Station of Wulanwusu, which was in an arid region of north-western China. Late sowing dates produced less yield and water-use efficiency than did the normal sowing dates. The yield increased with the increases of mean diurnal temperature range (DTR) from full bloom to maturity, mean temperature and sunshine hours (SH) during the whole growing season (WGS), accumulated temperature (AT) and days from squaring to anthesis and mean temperature during the reproductive growth stage. However, the main effect factors of meteorological parameters were AT from squaring to anthesis, mean temperature during the WGS and AT from sowing to emergence. The main effect factors of yield component were boll number per plant, gin turnout and boll weight. Boll number per plant suffered from mean DTR from boll setting to maturity and SH during the WGS. Gin turnout was affected by mean temperature during the WGS and mean DTR from boll setting to maturity. Sowing date, year and their interactions all significantly affected the yield. Sowing date was an important factor affecting the yield and reproductive duration. With climate change, an earlier planting date might be an efficient method of increasing yield.
 
Effects of management options on final biomass accumulation of maize variety HB 520 on a Nitisol, Acrisol and Ferralsol in Western Kenya. Trials were conducted in the short rainy season of 2008 and the long rainy season of 2009. Values are means of 4 replicates. 
Article
Low soil fertility and high weed infestation are the main culprits for the declining maize production in Western Kenya. Technology packages to address these constraints exist, but their effectiveness is likely to be influenced by variability in soil types and farm management practices in the region. Trials were conducted during the 2008/2009 cropping seasons to investigate the nutrient use efficiency and yield response of maize to some recommended management options for smallholder farmers on three dominant soil types of Western Kenya namely Acrisol, Nitisol and Ferralsol. Irrespective of seasons, average maize yields were highest on Nitisol (3.6 t ha-1) and lowest on Ferralsol (2.1 t ha-1). Maize yield gaps (difference between potentially achievable and actual yields) differed by season and soils with 4-5 t ha-1 on Nitisol and about 6 t grain ha-1 on Acrisol and Ferralsol. On Nitisol, the largest share of this yield gap (80%) was closed by the addition of mineral fertilizer, while on Ferralsol, reduced tillage could close 25-60% of the yield gap. The highest agronomic (13-39 kg grain kg-1 N) and physiological (50-160%) N use efficiencies were obtained with mineral fertilizers, while the addition of organic amendments resulted in the highest P use efficiency (15-154 kg grain kg-1 P), irrespective of soil type and season. As soil types and management options differentially affect yields and nutrient use efficiency of maize, there is a need for field-specific targeting of technologies to address maize production constraints in Western Kenya.
 
Top-cited authors
Ali Reza Sepaskhah
  • Shiraz University
Parvaiz Ahmad
  • GDC Pulwama J&K INDIA/ King Saud University Riyadh Saudi Arabia
Baby Joseph
  • Hindustan University / HITS
Riffat John
  • University of Kashmir
Rubina Lawrence
  • Sam Higginbottom University of Agriculture, Technology and Sciences