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Predicted increase in temperature variability can result in short duration of heat stress episodes coinciding with vulnerable reproductive processes leading to significant reduction in floret-fertility in crops. Recent knowledge on alternations in the pollen and stigmatic morphology, pollen biochemical and lipid composition, variable sensitivity of floral reproductive organs and differential temperature thresholds across crops advances the knowledge on heat stress induced reduction in seed-set and harvest index. Rapid increase in night-time temperature, leading to narrowing diurnal temperature amplitude is a major emerging threat to sustain crop productivity. Interestingly, wild wheat ( Aegilops spp.) with higher heat-tolerance and wild rice ( Oryza officinalis ) escaping damage by completing flowering during early morning hours, are examples of novel opportunities to breed field crops resilient to heat stress. Information on mechanisms leading to heat stress induced sterility is biased towards rice, wheat and sorghum, while the same across other field crops is limited. Hence, increasing research efforts in this direction is critical and timely. [ABSTRACT FROM AUTHOR]

Identifying lipids that experience coordinated metabolism during heat stress would provide information regarding lipid dynamics under stress conditions and assist in developing heat-tolerant wheat varieties. We hypothesized that co-occurring lipids, which are up-regulated or down-regulated together through time during heat stress, represent groups that can be explained by coordinated metabolism. Wheat plants ( Triticum aestivum L.) were subjected to 12 days of high day and/or night temperature stress, followed by a 4-day recovery period. Leaves were sampled at four time points, and 165 lipids were measured by electrospray ionization-tandem mass spectrometry. Correlation analysis of lipid levels in 160 leaf samples from each of two wheat genotypes revealed 13 groups of lipids. Lipids within each group co-occurred through the high day and night temperature stress treatments. The lipid groups can be broadly classified as groups containing extraplastidic phospholipids, plastidic glycerolipids, oxidized glycerolipids, triacylglycerols, acylated sterol glycosides and sterol glycosides. Current knowledge of lipid metabolism suggests that the lipids in each group co-occur because they are regulated by the same enzyme(s). The results suggest that increases in activities of desaturating, oxidizing, glycosylating and acylating enzymes lead to simultaneous changes in levels of multiple lipid species during high day and night temperature stress in wheat. [ABSTRACT FROM AUTHOR]

Abstract: Simulation studies have demonstrated that limited maximum transpiration rate (TR) at high air vapor pressure deficit (VPD) in water-limited environments could result in significant increases in sorghum yield. However, such a restriction on TR at high VPD has not been documented in sorghum. The objective of this study was to search within sorghum germplasm for the possibility of restricted TR at high VPD. Twenty six genotypes were selected for measurement of VPD response based on field observations including yield, leaf temperature, and the stay-green phenotype. These genotypes were grown in a greenhouse for about 24-d growth, and then placed into individual chambers in which VPD was varied and TR measured. The results of this study showed marked variation among sorghum genotypes in TR response to VPD. Seventeen genotypes were identified as exhibiting a breakpoint in their VPD response in the range from 1.6 to 2.7kPa, above which there was little or no further increase in TR. Therefore, these genotypes with a breakpoint have the possibility of soil water conservation when VPD during the midday cycle exceeds the breakpoint VPD. This trait would be desirable in less humid environments for increasing yields in water-deficit seasons. The observed range in the value of the BP among genotypes offers the possibility of developing genotypes with BP appropriate for specific environments. [ABSTRACT FROM AUTHOR]

Abstract: Global climate change, especially, increases in carbon dioxide (CO2) concentration and the associated increases in temperature will have significant impact on the crop production. Grain-sorghum [Sorghum bicolor (L.) Moench] cultivar DeKalb 28E was grown at daytime maximum/nighttime minimum temperature regimes of 32/22, 36/26, 40/30 and 44/34°C at ambient (350μmol CO2 mol−1) and elevated (700μmol CO2 mol−1) CO2 from emergence to maturity in controlled environments to quantify the effects of temperature and CO2 on the reproductive processes and yield. Growth temperatures of 40/30 and 44/34°C inhibited panicle emergence. Growth temperatures ≥36/26°C significantly decreased pollen production, pollen viability, seed-set, seed yield and harvest index when compared to 32/22°C. Percentage decreases in pollen viability, seed-set, seed yield and harvest index due to elevated temperature were greater at elevated CO2 when compared with ambient CO2. Elevated CO2 increased seed yield (26%) at 32/22°C, but decreased seed yield (10%) at 36/26°C. At high temperatures, elevated CO2 increased vegetative growth but not seed yield, thus, leading to decreased harvest index. We conclude that the adverse effects of elevated temperature on reproductive processes and yield of grain-sorghum were more severe at elevated CO2 than at ambient CO2; and the beneficial effects of elevated CO2 decreased with increasing temperature. The adverse temperature sensitivity of reproductive processes and yield at elevated CO2 was attributed to higher canopy foliage and seed temperatures. [Copyright &y& Elsevier]

Kidney bean (Phaseolus vulgaris L. cv. Montcalm) plants were grown under daytime maximum/nighttime minimum temperatures of 28/18, 34/24 and 40/30 °C at ambient carbon dioxide concentration (CO2; 350 μmol mol−1), and 28/18, 31/21, 34/24, 37/27 and 40/30 °C at elevated (twice-ambient) CO2, to characterize how increases in growth CO2 and temperature affected kidney bean leaf photosynthesis and carbohydrate metabolism. Elevated CO2 enhanced leaf photosynthetic rates by about 57% across the temperature regimes, compared with plants grown an ambient CO2. As growth temperature increased from 28/18 to 40/30 °C, leaf photosynthetic rates decreased at both ambient and elevated CO2. Growth at either elevated temperature or CO2 decreased activity, protein content and activation of the primary photosynthetic enzyme ribulose 1,5-bisphosphate carboxylase-oxygenase (Rubisco). Elevated CO2 increased activities of sucrose-phosphate synthase (SPS) and adenosine-5′-diphosphoglucose pyrophosphorylase (AGP) and accumulation of soluble sugars and starch across all temperatures, compared with plants grown at ambient CO2. At elevated CO2, growth temperatures above 34/24 °C significantly increased leaf carbohydrates (total soluble sugars and starch) and activity of AGP. The up-regulation of leaf carbohydrate metabolism enzymes under elevated CO2 plus temperature would be beneficial for growth and productivity of kidney bean in future climates. [Copyright &y& Elsevier]

Continuing increases in atmospheric carbon dioxide concentration (CO2) will likely be accompanied by global warming. Our research objectives were (a) to determine the effects of season-long exposure to daytime maximum/nighttime minimum temperatures of 32/22, 36/26, 40/30 and 44/34°C at ambient (350 μmol mol−1) and elevated (700 μmol mol−1) CO2 on reproductive processes and yield of peanut, and (b) to evaluate whether the higher photosynthetic rates and vegetative growth at elevated CO2 will negate the detrimental effects of high temperature on reproductive processes and yield. Doubling of CO2 increased leaf photosynthesis and seed yield by 27% and 30%, respectively, averaged across all temperatures. There were no effects of elevated CO2 on pollen viability, seed-set, seed number per pod, seed size, harvest index or shelling percentage. At ambient CO2, seed yield decreased progressively by 14%, 59% and 90% as temperature increased from 32/22 to 36/26, 40/30 and 44/34°C, respectively. Similar percentage decreases in seed yield occurred at temperatures above 32/22°C at elevated CO2 despite greater photosynthesis and vegetative growth. Decreased seed yields at high temperature were a result of lower seed-set due to poor pollen viability, and smaller seed size due to decreased seed growth rates and decreased shelling percentages. Seed harvest index decreased from 0.41 to 0.05 as temperature increased from 32/22 to 44/34°C under both ambient and elevated CO2. We conclude that there are no beneficial interactions between elevated CO2 and temperature, and that seed yield of peanut will decrease under future warmer climates, particularly in regions where present temperatures are near or above optimum. [ABSTRACT FROM AUTHOR]

Identifies the times during reproductive development of peanut crops when hot days reduce yield. Relationship between flower production and sensitivity to heat stress; Reduction of proportion of flowers producing pegs; Linking of heat stress during floral bud development to peg number.

Conservation practices such as green manures and no-tillage can reduce soil erosion, enhance soil biological activity, increase water storage in soils, and provide nitrogen (N) in support of winter wheat (Triticum aestivum L.). However, green manures utilize soil water during the summer months, and such water depletion may negatively impact production by wheat in ecoregions with limited water resources. This 5-year study quantified the impacts of tillage systems and green manures on water storage efficiency (WSE) during summer, water use efficiency (WUE), and grain yield of winter wheat. The study was conducted during 2011–2016 in the United States (US) Southern Great Plains (SGP). Three legumes as green manures (cowpea, pigeon pea, and soybean) were compared with summer fallow and three levels of applied inorganic N (0, 45 and 90 kg N ha-1) at wheat planting, under conventional and no-till cultivation. Summer WSE was significantly (P < 0.05) reduced in response to green manures; summer fallow was also inefficient in storing soil water. Grain yield and WUE of wheat were reduced in response to green manures compared to summer fallow during dry years but there were no differences during wet or normal rainfall years. No till significantly increased WSE under all treatments, and reduced evapotranspiration during a subset (either summer or wheat growing season) of years but did not affect amounts of soil water. Our results demonstrate replacing summer fallow in continuous systems of winter wheat with green manures have limited effects on improving water availability or efficiencies in water use by wheat. More-effective approaches for using green manures to support winter wheat in the SGP include opportunity cropping during years with adequate moisture to support double-cropping or utilizing more water-efficient legumes or cropping systems. • WSE, WUE, and wheat yield responses to different crop rotations were assessed. • Summer fallow was inefficient in storing precipitation water. • Replacing the summer fallow with cover crops did not increase WSE. • Planting cover crops helped to increase system WUE during normal or wet years. • Winter wheat yield response to cover crop biomass production was negatively linear. [ABSTRACT FROM AUTHOR]

Canola (Brassica napus L.) is a dual-purpose oilseed crop with a potential to close an increasing demand/supply gap for biofuel production. To increase oil production, it is imperative to identify the best production regions and to understand these environments the production environments to inform management decisions. The aims of this study were to) characterize water stress patterns in the major US winter canola production and its implications to determine regions with similar yield and oil production. With this purpose, a field observed dataset was curated from the National Winter Canola Variety Trial (NWCVT). This dataset comprises 88 sites covering around 26 US states for the 2003–2019 time period and includes phenology data and the description of the management practices for more than 400 varieties. The observed flowering date, maturity date, yield, and oil concentration were used to train and evaluate APSIM Canola. Crop phenology and seed yield presented adequate model performance (Normalized Root Mean Square Error (NRMSE)= 0.08, 0.19; Kling-Gupta model Efficiency (KGE)= 0.89, 0.68, respectively) while model performance was inferior for oil concentration (NRMSE=0.49, KGE=0.08). Three spatial clusters were defined based on water stress frequency, yield, and oil concentration. Geographically from East to West, yield and oil productivity decreased with increasing water stress frequency. This study provides new insights on identifying potential regions for oil production and on closing the increasing demand/supply gap. [Display omitted] • Water stress in grain filling significantly affects yield and oil (70 % site-years) • Three spatial clusters were determined by water stress frequency, yield, and oil • Eastern and central regions showed the highest yields (∼4 Mg ha−1) with < 25 % stress • Eastern and central regions evidenced high potential for increased oil productivity [ABSTRACT FROM AUTHOR]

A limited-transpiration (TR lim ) trait has been identified in many crop species, including sorghum ( Sorghum bicolor (L.) Moench), that results in restricted transpiration rate under high vapor pressure deficits (VPD). The benefit of TR lim is that under high midday-VPD conditions crop water loss is limited so that there is water conservation and positions the crop to better withstand later-season drought. Previous studies performed at 31 °C found that TR lim was commonly expressed among sorghum genotypes. It was also found that those lines with low VPD breakpoints for expression of the TR lim trait exhibited insensitivity in transpiration rate to being fed silver ions. However, it is uncertain how applicable these previous results obtained at 31 °C might be at higher temperature that may exist at midday in regions where sorghum is commonly grown. The current study tested for the expression of TR lim at 37 °C in 16 sorghum genotypes previously found to express the trait at the lower temperature. Only three of the genotypes sustained expression of TR lim at 37 °C. These results indicate that for environments where temperature may commonly reach or exceed 37 °C, sorghum genotypes have been favored that acclimate to the high temperature by losing the TR lim trait. In conditions in which very high temperatures threaten crop heat stress, those genotypes that lose the TR lim trait at high temperature may be more desirable since increasing transpiration rates at these temperatures can result in leaf cooling. The silver test failed to discriminate genotypes for expression of the TR lim trait at high temperature. [ABSTRACT FROM AUTHOR]

Multiple entry selections of big bluestems and three native C4 grass species, including switchgrass, miscanthus, and Conservation Reserve Program (CRP) mixture grass, were evaluated for their chemical composition and ethanol yields via diluted sulfuric acid pretreatment following simultaneous saccharification and fermentation (SSF). Big bluestem and switchgrass had a similar glucan content that was significantly higher than miscanthus and CRP grass. Big bluestem had the highest average mass recovery (55.56%) after acid pretreatment, and miscanthus had the lowest mass recovery (46.3%). A positive correlation was observed between glucan recovery and mass recovery. No significant difference in average efficiency of SSF was observed among four native grasses, but ethanol yields from big bluestem entries, which averaged 26.2%, were consistently greater than the other three grasses. The highest ethanol yield among the 10 entries was from big bluestem cultivar KAW (27.7%). Approximately 0.26 kg ethanol with 9.4 g/L concentration can be produced from 1 kg of big bluestem biomass under current processing conditions. A negative relationship exists between lignin content and the efficiency of SSF with R = −0.80, and a positive relationship exists between ethanol yield and glucan content with R = 0.71. [ABSTRACT FROM AUTHOR]

At the onset of COVID‐19, researchers quickly recognized the need for research on the consequences of the pandemic for agricultural and food systems, both in terms of immediate impacts on access to inputs and labor, disruptions in transportation and markets, and the longer‐term implications on crop productivity, income, and livelihoods. Vegetable production and supply chains are particularly vulnerable due to the perishable nature of the products and labor‐intensive production practices. The purpose of this study was to understand the impacts of COVID‐19 on vegetable production in Burkina Faso in terms of both the biophysical aspects such as yields and access to inputs and socioeconomic aspects such as access to labor, markets, and social services. A survey was developed to better understand smallholder farmer experiences regarding the impacts of COVID‐19 on their vegetable production systems and social well‐being. The survey was administered (between August and October 2020) with smallholder farmers (n = 605) in 13 administrative regions covering all agroecological zones of Burkina Faso. The survey results clearly show impacts of COVID‐19 on vegetable systems, including a reduction in access to inputs, a reduction in yields, a loss of income, reduced access to local and urban markets, reduced access to transportation, and an increase in post‐harvest loss. Market access, distribution, and disruptions were a major shock to the system. Results also showed an increase in women's labor in the household, and for youth, an increase in unemployment, job loss, and concerns of poverty. Finally, food security and social supports were highlighted as major issues for resilience and livelihoods. The results from this survey should be helpful to policymakers and researchers to develop policies and strategies to minimize the negative impacts of this ongoing pandemic on the agri‐food systems and support smallholder farmers to overcome stress caused by COVID‐19. [ABSTRACT FROM AUTHOR]

Abstract: Sorghum is one of the most drought-tolerant grain crops and is used in biofuel production. Since sorghum is often exposed to drought and high temperature (heat) stress, this study investigated the effect of stress applied at different phenological stages of crop development on the glucose levels in grain and subsequent ethanol production. Short season sorghum hybrid DK-28E grown under controlled environment was exposed to drought and heat stress at five different stages of growth, namely: (1) pre-flowering (boot leaf emergence) to flowering, (2) flower to seed-set, (3) seed-set to early seed-fill, (4) early seed-fill to mid seed-fill, and (5) mid seed-fill to late seed-fill stage. Drought stress at any of the growth stages did not statistically affect either the glucose content or the ethanol production compared to the control (337mg/g), although the ethanol yield increased up to 4.5% (352mg/g) in flowering to seed-set stage. Heat stress, on the other hand, significantly reduced the glucose release and ethanol yield compared to the control (322mg/g). Marginal ethanol yield reduction by 9% (293mg/g) and 8.3% (295mg/g) was seen in plants stressed during early seed-fill to mid seed-fill and mid seed-fill to late seed-fill stages, respectively. The results suggest that the phenological stage when sorghum is exposed to stress affects the ethanol yield. Overall, from the point of ethanol yield, it appears that grain sorghum cultivated in semi-arid regions where heat and drought stress are prevalent can be used for biofuel production. However, economic viability of ethanol production, especially of grain sorghum from high temperature stress needs to be investigated. [Copyright &y& Elsevier]

Nitrogen (N) metabolism is a major research target for increasing productivity in crop plants. In maize (Zea mays L.), yield gain over the last few decades has been associated with increased N absorption and utilization efficiency (i.e. grain biomass per unit of N absorbed). However, a dynamical framework is still needed to unravel the role of internal processes such as uptake, allocation, and translocation of N in these adaptations. This study aimed to 1) characterize how genetic enhancement in N efficiency conceals changes in allocation and translocation of N, and 2) quantify internal fluxes behind grain N sources in two historical genotypes under high and low N supply. The genotypes 3394 and P1197, landmark hybrids representing key eras of genetic improvement (1990s and 2010s), were grown under high and low N supply in a two-year field study. Using stable isotope 15N labelling, post-silking nitrogen fluxes were modeled through Bayesian estimation by considering the external N (exogenous-N) and the pre-existing N (endogenous-N) supply across plant organs. Regardless of N availability, P1197 exhibited greater exogenous-N accumulated in leaves and cob-husks. This response was translated to a larger amount of N mobilized to grains (as endogenous-N) during grain-filling in this genotype. Furthermore, the enhanced N supply to leaves in P1197 was associated with increased post-silking carbon accumulation. The overall findings suggest that increased N utilization efficiency over time in maize genotypes was associated with an increased allocation of N to leaves and subsequent translocation to the grains. • Bayesian modelling and 15N analysis were combined to estimate N allocation in maize. • Modern maize plants evidenced an improved post-silking N partitioning to leaves. • Greater N allocation to leaves resulted in an increased post-silking carbon fixation. • Internal translocation to the grains was improved due to larger supply from leaves. [ABSTRACT FROM AUTHOR]

Long‐term selection in maize (Zea mays L.) favored single‐stalked phenotypes limiting vegetative growth. However, reduced plant densities create conducive environments to the expression of vegetative branches called tillers. Tiller expression has motivated discussions about its yield effect in variable environments, but tiller research is lacking for modern corn genotypes. The objectives of this study were to (a) quantify the relative importance of management, environment, and interactions on the yield effect of tiller expression for two modern genotypes; (b) understand effects of observed tiller density, plant density, and their interaction on yield; and (c) identify key environmental determinants of yield response to tiller density in modern genotypes. In 10 environmentally diverse site‐years across Kansas, tiller presence and removal were evaluated in two commercial corn hybrids (P0657AM and P0805AM) across three target plant density levels (25,000, 42,000, and 60,000 plants ha−1). Yields were increased or unaffected by greater plant densities and tiller presence within site‐years. Environments varied in yield responsiveness to tiller density, but fine‐tuning plant density was needed to maximize yields. Sites with yields most responsive to tiller density were characterized by good soil properties and photothermal quotient values (e.g., soils with high organic matter and climates with greater solar radiation and cooler temperatures). Favorable growing conditions can be exploited by plasticity traits such as tillering in unpredictable environments with annually variable optimum plant densities while limiting potential yield loss and producer risk due to disproportionate plant density. Core Ideas: Tiller presence never reduced yield in evaluated environments and plant densities.In favorable scenarios, corn tillers have plant density compensation potential.Plant density adjustment was necessary to maximize yield for all environments.Corn tillers have plasticity potential to optimize defensive management strategies. [ABSTRACT FROM AUTHOR]

Rapid increases in minimum night temperature than in maximum day temperature is predicted to continue, posing significant challenges to crop productivity. Rice and wheat are two major staples that are sensitive to high night‐temperature (HNT) stress. This review aims to (i) systematically compare the grain yield responses of rice and wheat exposed to HNT stress across scales, and (ii) understand the physiological and biochemical responses that affect grain yield and quality. To achieve this, we combined a synthesis of current literature on HNT effects on rice and wheat with information from a series of independent experiments we conducted across scales, using a common set of genetic materials to avoid confounding our findings with differences in genetic background. In addition, we explored HNT‐induced alterations in physiological mechanisms including carbon balance, source–sink metabolite changes and reactive oxygen species. Impacts of HNT on grain developmental dynamics focused on grain‐filling duration, post‐flowering senescence, changes in grain starch and protein composition, starch metabolism enzymes and chalk formation in rice grains are summarized. Finally, we highlight the need for high‐throughput field‐based phenotyping facilities for improved assessment of large‐diversity panels and mapping populations to aid breeding for increased resilience to HNT in crops. Impact of high night temperature on grain yield and quality in field crops, captured across spatial scales, allows the identification of tolerant germplasm, traits and mechanisms from controlled environments that have relevance under field conditions. [ABSTRACT FROM AUTHOR]

The demand for food production has been constantly increasing due to rising population. In developed countries, for example, the emergence of regional production of old grains that are rarely utilized, along with the production of commonly consumed grains, has gained importance in recent years. These grains, known collectively as ancient or heirloom grains, have offered both farmers and consumers novel ways of cultivation and products with interesting taste, characteristics and nutritional value. Among the 30 000 plant species known, only five cereals currently provide more than 50% of the world's energy intake – bread wheat (Triticum aestivum), rice (Oryza sativa), sorghum (Sorghum bicolor), millets (Panicum sp.) and maize (Zea mays). The excessive utilization of these selected species has a great potential to cause genetic losses and difficulty in bridging future agricultural demands. Teff (Eragrostis tef), an ancient grain extensively cultivated in countries like Eritrea and Ethiopia, provides promising alternatives for new food uses since its nutritional value is significantly higher than most others cereal grains. The absence of gluten allows flexibility in food utilization since it can be directly substituted to gluten‐containing products. The grain also offers an excellent balance of essential amino acids and minerals, which can fulfil the recommended daily intake and eliminates the need for fortification and enrichment. This review provides a general overview of the physical properties and nutritional composition of teff grains related to processing and applications in the food and feed industries. The current status of teff utilization, as well as the challenges in production and commercialization, and future opportunities is presented and discussed. [ABSTRACT FROM AUTHOR]

Despite the ability of sorghum [Sorghum bicolor (L.) Moench] to withstand harsh environmental conditions, it is susceptible to water‐deficit stress during grain filling. To identify postflowering, drought‐tolerant sorghum genotypes, parents of nested association mapping populations were evaluated under controlled and water‐deficit conditions in greenhouse and field conditions. In both experiments, water‐deficit stress was imposed by withholding water during the grain‐filling period. In field experiments, rootzone soil moisture was measured weekly using a neutron probe to quantify the plant available water under well‐watered and water‐deficit conditions. Investigations were focused on determining the variability in the grain‐filling pattern across different positions within the panicles (intra‐panicle) of 11 different sorghum genotypes. Water‐deficit conditions characterized by low plant available water had a consistently negative association with grain number along different positions in the panicle. Our findings indicate that maintaining grain numbers per panicle under postflowering water deficit is more important than increasing individual grain weight. Among the tested genotypes, SC35 and SC1103 were most tolerant to water‐deficit conditions under greenhouse and field conditions, respectively. Currently available biparental populations developed using these genotypes provide an opportunity to enhance tolerance to postflowering water‐deficit stress in sorghum. Core Ideas: Water‐deficit stress affects grain numbers at different positions within a panicle.Individual grain weight is not affected by position on a panicle.Maintaining seed numbers is key under postflowering water‐deficit stress.Embryonic abortion and panicle architecture are areas for further investigation. [ABSTRACT FROM AUTHOR]

The photoassimilates and nitrogen (N) allocation in grain crops can be studied via the harvest index (HI) and the N harvest index (NHI). These two variables should be considered in breeding programs seeking more effective use of resources in maize (Zea mays L.) and other grain crops. Molecular biotechnology has emerged as a complement to improve not only maize grain yield but also resource utilization efficiency. A recent study reported a beneficial impact of increasing and extending the expression of a maize MADS-box transcription factor (zmm28) on the NHI. This research aimed to further identify enhancements of C-N partitioning (HI, NHI) in DP202216 maize hybrids recognizing the main physiological and morphological traits associated to the C-N dynamics via in-season intra-canopy measurements. Two DP202216 elite hybrids were evaluated with their respective wild-type (WT) controls during two field growing seasons under two N regimes. The N nutrition index (NNI), as crop N status, was quantified to avoid misinterpretations of the results. The DP202216 trait showed, on average, a ∼6% increase in the HI with a concomitant positive impact of ∼9% in the NHI across hybrids, N regimes, and seasons. Those increases were consistent at different crop NNI. After accounting for the NNI, it was shown that the increases in both HI and NHI were supported by the accumulation of more N in leaves (mainly in both lower and middle sections of the canopy vertical profile) and more water-soluble carbohydrates (WSC) in stems before flowering, combined with more aggressive post-anthesis remobilization. In this study, it was shown an increase in the efficient use of crop resources in DP202216 hybrids with respect to their isogenic WT controls at similar NNI via increments in C and N partitioning (HI and NHI). This physiological and morphological understanding of C- and N-related traits addressed the challenge of optimizing the effective use of resources in maize breeding programs. To better understand traits by management interactions with yield and yield stability, DP202216 hybrid evaluations across a broad range of commercially relevant N scenarios would be valuable. • Zmm28 hybrids increased both the harvest index (HI) and nitrogen HI (NHI). • Zmm28 hybrids displayed more leaf N and stem water-soluble carbohydrates (WSC) accumulation. • The increase in HI and NHI was supported by greater WSC (stem) and N (leaf and stem) remobilization. • This study provides knowledge for optimizing the effective use of resources in grain crops. [ABSTRACT FROM AUTHOR]

Low productivity, yield stagnation, and reduction of water use, altogether with increased susceptibility to climate variability represent a challenge for agricultural producers in the United States (US) central Great Plains. In this context, a more holistic assessment of the cropping systems should be considered as a critical aspect for developing more sustainable rainfed agricultural systems in this region. The objectives of this study were to: i) quantify the fallow precipitation storage efficiency for a continuous winter wheat rotation (traditional rotation), ii) analyze and compare glucose-equivalent yields and economic results for different cropping sequences, and iii) determine efficiency components of the rotation for components such as precipitation use efficiency (PUE) and nitrogen (N) partial factor productivity (PFP N) for different cropping sequences and N management. A three-year field experiment (2019–2022) was conducted near Manhattan, Kansas (US), under rainfed conditions. Treatments included eleven crop rotations, combining forage and grain purpose crops, and two N management, standard and progressive. An economic analysis based on the yield data combined with historical budgets was developed to compare income, expenses, and economic margins of different cropping systems. No-till summer fallow represented low (<20%) precipitation storage efficiency in the continuous winter wheat cropping system. In terms of cumulative dry matter and glucose-equivalent yields, greater overall productivity was feasible for more intensified systems and when forage crops were included in the crop sequence (e.g., ∼15 vs. ∼30 Mg glucose equivalent (GE) ha−1, for wheat monoculture and forage purpose only rotations, respectively). However, cropping sequences with high frequency of forages had negative economic margins (US$ -1113 to US$ -626 ha−1), while winter wheat combined with grain double crop rotation attained the highest positive economic returns (US$ 571 ha−1). Finally, progressive N-management increased PFP N relative to the standard management (63.5 vs. 54.2 kg GE kg N−1, respectively) while maintaining PUE for several intensified crop rotations. Expanding the adoption of more intensified and diversified cropping systems could increase resource capture and use efficiency and productivity in the dominant continuous winter wheat systems in the US central Great Plains. [Display omitted] • No-till summer fallow had low (<20%) precipitation storage efficiency. • Including annual and perennial forages increased the productivity of crop rotations. • Double cropping after winter wheat resulted in the highest net income. • Intensive nitrogen fertilizer management increased nutrient partial factor productivity. [ABSTRACT FROM AUTHOR]

Unusual daily temperature fluctuations caused by climate change and climate variability adversely impact agricultural crop production. Since plants are immobile and constantly receive external environmental signals, such as extreme high (heat) and low (cold) temperatures, they have developed complex molecular regulatory mechanisms to cope with stressful situations to sustain their natural growth and development. Among these mechanisms, non-coding RNAs (ncRNAs), particularly microRNAs (miRNAs), small-interfering RNAs (siRNAs), and long-non-coding RNAs (lncRNAs), play a significant role in enhancing heat and cold stress tolerance. This review explores the pivotal findings related to miRNAs, siRNAs, and lncRNAs, elucidating how they functionally regulate plant adaptation to extreme temperatures. In addition, this review addresses the challenges associated with uncovering these non-coding RNAs and understanding their roles in orchestrating heat and cold tolerance in plants. [Display omitted] • Frequent episodes of cold and heat stress adversely affect crop growth. • The role of non-coding RNAs (ncRNAs) in regulating cold and heat tolerance has gained attention. • The complex mechanisms of ncRNA-mediated cold and heat tolerance need deeper exploration. • Novel ncRNAs offer potential to develop climate-resilient crops. [ABSTRACT FROM AUTHOR]

Quantifying yield gaps (potential minus actual yield) and identifying management practices to close those gaps is critical for sustaining high-yielding production systems. The objectives of this study were to: 1) calibrate and validate the APSIM maize and soybean models using local field experimental data and 2) use the calibrated model to estimate and explain yield gaps in the long term as a function of management (high- vs low-input) and weather conditions (wet-warm, wet-cold, dry-warm and dry-cold years) in the western US Corn Belt. The model was calibrated and validated using in-season crop growth data from six maize-soybean rotations obtained in 2014 and 2015 in Kansas, US. Experimental data included two management systems: 1) Common Practices (CP, low-input), wide row spacing, lower seeding rate, and lack of nutrient applications (except N in maize), and 2) Intensified Practices (IP, high-input), narrow rows, high seeding rate, and balanced nutrition. Results indicated that APSIM simulated in-season crop above ground mass and nitrogen (N) dynamics as well yields with a modeling efficiency of 0.75 to 0.92 and a relative root mean square error of 18 to 31%. The simulated maize yield gap across all years was 4.2 and 2.5 Mg ha−1 for low- and high-input, respectively. Similarly, the soybean yield gap was 2.5 and 0.8 Mg ha−1. Simulation results indicated that the high-input management system had greater yield stability across all weather years. In warm-dry years, yield gaps were larger for both crops and water scenarios. Irrigation reduced yield variation in maize more than in soybean, relative to the rainfed scenario. Besides irrigation, model analysis indicated that N fertilization for maize and narrow rows for soybean were the main factors contributing to yield gains. This study provides a systems level yield gap assessment of maize and soybean cropping system in Western US Corn Belt that can initiate dialogue (both experimental and modeling activities) on finding and applying best management systems to close current yield gaps. • High-input system had more yield stability across weather patterns. • Intensified management reduced in half the yield gap under irrigation. • Simulated maize yield was more sensitive to weather changes than soybean. [ABSTRACT FROM AUTHOR]

The superior agronomic and human nutritional properties of grain legumes (pulses) make them an ideal foundation for future sustainable agriculture. Legume‐based farming is particularly important in Africa, where small‐scale agricultural systems dominate the food production landscape. Legumes provide an inexpensive source of protein and nutrients to African households as well as natural fertilization for the soil. Although the consumption of traditionally grown legumes has started to decline, the production of soybeans (Glycine max Merr.) is spreading fast, especially across southern Africa. Predictions of future land‐use allocation and production show that the soybean is poised to dominate future production across Africa. Land use models project an expansion of harvest area, whereas crop models project possible yield increases. Moreover, a seed change in farming strategy is underway. This is being driven largely by the combined cash crop value of products such as oils and the high nutritional benefits of soybean as an animal feed. Intensification of soybean production has the potential to reduce the dependence of Africa on soybean imports. However, a successful "soybean bonanza" across Africa necessitates an intensive research, development, extension, and policy agenda to ensure that soybean genetic improvements and production technology meet future demands for sustainable production. Soybean is fast becoming an increasingly attractive cash crop in Africa. We have examined current and future legume production in Sub‐Saharan Africa using a modelling approach based on available FAO data to provide projections for 2050. These data predict a large expansion in African soybean production. The resultant great potential for the amelioration of poverty, hunger, and malnutrition will be a major driver for farmers and producers to overcome the significant challenges that might otherwise impede soybean production in Africa. [ABSTRACT FROM AUTHOR]

The objectives were to (a) quantify the effects of high daytime temperature (HDT) from gametogenesis to full bloom on photosynthesis and pod set in soybean (Glycine max L. Merril) genotypes and (b) assess the relationships among photosynthesis, cardinal temperatures for pollen germination, in vitro pollen germination percentage, canopy reflectance, and pod‐set percentage. Three field experiments were conducted, and Experiment I had HDT between gametogenesis and full bloom (36.5°C to 38.6°C) compared with Experiments II and III (29.5°C to 31.6°C; optimum temperature). HDT decreased photosynthesis (22%) and pod‐set percent (11%) compared with Experiment III. Cultivars had higher photosynthesis and pod‐set percent than plant introduction (PI) lines. The cultivars (i.e., IA3023 and KS4694) and PI lines (i.e., PI393540 and PI588026A) were HDT tolerant and susceptible, respectively. The decreased pod‐set percentage in susceptible genotypes (PI lines) was associated with pollen characteristics. Significant positive (r2 ≥ 0.67) association between photosynthesis, cardinal temperatures for pollen germination (Topt and Tmax) with pod‐set percentage was observed. However, a negative (r2 ≥ −0.43) association between photosynthesis and pod set with canopy reflectance at visible spectrum was observed. In vitro pollen germination and canopy reflectance at visible spectrum can be used as a high‐throughput phenotypic tool for breeding HDT‐tolerant genotypes. Mechanistic understanding of impacts of high daytime temperature on reproductive success in soybean is important for development of high‐temperature‐tolerant genotypes. The study showed that under field conditions, an increase in daytime temperature from gametogenesis to full bloom decreased pod‐set percentage in diverse soybean genotypes due to loss of pollen viability. There was a strong positive association among pod‐set percentage, cardinal temperatures for pollen germination (Topt and Tmax) and in vitro pollen germination. Genotypes tolerant to high daytime temperatures were identified. In vitro pollen germination at 38°C and canopy reflectance at visible spectrum can be used as high‐throughput phenotypic tool for identifying tolerant genotypes. [ABSTRACT FROM AUTHOR]

Region-specific guidelines for maize in the US Great Plains are needed to account for variability in farmer practices and inherent soil and climate differences. Therefore, it becomes critical to define environment tailored management strategies for maize crop to improve and sustain yields over time. The aims of this study were to: i) define homogenous maize yield environments classified as related to the maximum yield and its stability over time in the US central Great Plains region; ii) explore the combinations of planting date and hybrid maturity that lead to optimal yield for each of the previously defined homogenous maize yield environments; and iii) identify environments presenting different windows for maximizing yields (combinations of planting date by hybrid maturity). Hybrid maturity (growth cycle) by planting date combinations were explored at 70 sites within central and eastern Kansas and northern Oklahoma (herein defined as the US central Great Plains region) using 30 years of historical weather data. In addition to the analysis of an extensive maize field dataset, a crop growth model, Agricultural Production Systems Simulator (APSIM), was utilized to evaluate the crop yield and phenology of all hybrid maturity by planting date combinations to define environment tailored management strategies. The simulated yields were spatially clustered based on attainable yield and stability over time to delimit more homogeneous productivity environments. Overall, greater yields were attained with long-maturing hybrids (comparative relative maturity, CRM, 101 and 115). Delaying the planting date from April to mid-May decreased yield in eastern environments. Moreover, late planting maintained yields and increased stability in central environments. For central Kansas and Oklahoma, anticipation of physiological maturity date (3–16 days) with reduced yield penalties (<5%) were possible by using short-season hybrid maturities (CRM 85). Future scenarios for intensification could be explored in those environments presenting more windows for maximizing yields, either with early planting and harvest dates or via late planting providing time for a short crop before maize. Adoption of more region-specific guidelines for maize management could help to optimize yield and its stability over time and seek further opportunities to diversify risk and intensify our current maize-based farming systems in the US central Great Plains. • Higher yields were attained with long-maturing hybrids (CRM 101 and 115). • Delays in planting date after mid-May decreased yield in eastern environments. • Late planting maintained yields and increased stability in central environments (CE). • CRM 85 reached maturity earlier with similar yields compared to longer CRMs in CE. • Self-report on farm yield data supported the simulated yield trends. [ABSTRACT FROM AUTHOR]

Rice is highly sensitive to temperature stress (cold and heat), particularly during the reproductive and grain-filling stages. In this review, we discuss the effects of low- and high-temperature sensitivity in rice at various reproductive stages (from meiosis to grain development) and propose strategies for improving the tolerance of rice to terminal thermal stress. Cold stress impacts reproductive development through (i) delayed heading, due to its effect on anther respiration, which increases sucrose accumulation, protein denaturation and asparagine levels, and decreases proline accumulation, (ii) pollen sterility owing to tapetal hypertrophy and related nutrient imbalances, (iii) reduced activity of cell wall bound invertase in the tapetum of rice anthers, (iv) impaired fertilization due to inhibited anther dehiscence, stigma receptivity and ability of the pollen tube to germinate through the style towards the ovary, and (v) floret sterility, which increases grain abortion, restricts grain size, and thus reduces grain yield. Heat stress affects grain formation and development through (i) poor anther dehiscence due to restricted closure of the locules, leading to reduced pollen dispersal and fewer pollen on the stigma, (ii) changes in pollen proteins resulting in significant reductions in pollen viability and pollen tube growth, leading to spikelet sterility, (iii) delay in heading, (iv) reduced starch biosynthesis in developing grain, which reduces starch accumulation, (v) increased chalkiness of grain with irregular and round-shaped starch granules, and (vi) a shortened grain-filling period resulting in low grain weight. However, physiological and biotechnological tools, along with integrated management and adaptation options, as well as conventional breeding, can help to develop new rice genotypes possessing better grain yield under thermal stress during reproductive and grain-filling phases. [ABSTRACT FROM AUTHOR]

Water is the major factor limiting crop production in western Kansas due to declining groundwater levels in the Ogallala aquifer resulting from withdrawals for irrigation exceeding recharge rates coupled with erratic semi-arid rainfall. Study objectives were to assess yield and water productivity of water limited cropping systems in western Kansas using DSSAT-CSM (Decision Support System for Agrotechnology Transfer Cropping Systems Model). The cropping systems evaluated included continuous (corn, wheat, and grain sorghum) and rotation (corn-wheat, corn-wheat-grain sorghum, and corn-wheat-grain sorghum-corn). Results showed that the model adequately reproduced measured days to flowering and maturity as well as yield and aboveground biomass of all three crops. Crop rotation improved water productivity of corn. Under deficit irrigation, corn in rotation produced higher yields, crop water productivity, and irrigation water use efficiency compared to continuous corn, implying that crop rotation is a better option under limited well capacities. Under full irrigation, yield and water productivity of continuous wheat were lower than wheat in rotation. In contrast, continuous wheat yields under deficit irrigation were better than under crop rotation. Deficit irrigation substantially improved irrigation water use efficiency of grain sorghum under both continuous and crop rotations. Long–term average grain sorghum yields under rotation were higher than those of continuous grain sorghum. Indicating grain sorghum should be grown in rotation under deficit irrigation. This research did not simulate the impacts of pests, weeds and diseases, hail and freeze damage on crop yield. However, the study identifies cropping systems that are more likely to produce highest water productivity under semi-arid climate similar to that in western Kansas. [ABSTRACT FROM AUTHOR]

Pearl millet (Pennisetum glaucum L.) is a staple food crop for rural households in Senegal. However, yields remain low due to reduced precipitation and low adoption of agricultural technologies. This study aims to (i) calibrate and evaluate the performance of the Agricultural-Production-System-sIMulator (APSIM)-Millet model to simulate crop phenology and grain yield, and (ii) develop regional-specific recommendations based on management scenarios for pearl millet in Senegal. The APSIM-Millet model was adjusted for early- and late-flowering landraces, with field-data from 351 locations during 2016–2021. Independent datasets were used to evaluate the agreement of crop model outcomes with (i) crop phenology (with a root mean square error, RMSE, of 2.4 days for early- flowering and 3.7 days for late-flowering landraces), and ii) grain yield (with average RMSE of 439 kg ha-1), across locations. For all Senegal millet producing districts, crop management scenarios were simulated by combining: six levels of nitrogen (N) fertilization, three plant-densities, and three planting-dates. These scenarios were compared against a literature-reported standard management. The implementation of the recommended management practices can increase farmer yields by two-fold in Senegal, mainly by increasing plant-density, N fertility, and by adjusting planting date to better match precipitation with the period of greater crop water demand. [Display omitted] • Management strategies were designed for millet productive regions in Senegal. • Recommended practices doubled millet yield relative to current farming strategies. • Recommended practices increased ∼3-fold yield/precipitation ratio. • Adjusting planting date was critical to better match water supply with crop demand. [ABSTRACT FROM AUTHOR]

Canola (Brassica napus L.) is a major oilseed crop for edible and industrial uses. Climate change, characterized by extreme heat and drought conditions, can affect canola seed yield and quality (protein and oil), restricting grower capacity to keep pace with growing demand. However, estimating the influence of future climate on such complex traits is challenging due to biophysical interactions and crop adaptations to abiotic stresses. Current scientific literature reports contrasting impacts on the effect of heat and drought for canola productivity, mainly linked to changes in magnitude and duration of the stress. To better understand how drought and heat affect canola seed yield and quality (mainly protein and oil), a meta-analysis was executed to compile a total of 39 papers (1794 observations). The aims of this research were to i) quantify the impact of different timing and duration of heat and drought stresses on canola seed yield, oil yield, and seed quality (oil and protein concentration), and ii) study the effect of short-term stresses on seed quality, yield and its components (seed number and seed weight). This review study highlighted the magnitude and direction of overall and different stress impacts on canola; and some of the main limitations in the current scientific literature. Briefly, the main outcomes of this review highlighted that i) early heat stress(before end of flowering) had the largest impact on canola seed yield, as a short stress, ii) drought caused greatest yield impact when imposed for a long duration during flowering or a shorter duration during pod setting, and iii) short stresses had large impacts on seed oil concentration mainly during pod setting. More studies with standard stress levels and detailed information of abiotic stresses on reproductive growth stages are needed. This meta-analysis provides critical information for crop management, guiding development of cultivars linked to tolerance to abiotic stresses for breeding programs, and the future direction of canola adoption and production. • Contrasting heat and drought impacts on canola/rapeseed were reported in the literature. • This meta-analysis dissected abiotic stress timing and duration. • Highest negative impacts on yield were observed with stresses imposed before the end of flowering. • Seed oil and protein concentration were affected following abiotic short stresses during pod setting. [ABSTRACT FROM AUTHOR]

Soybean [ Glycine max (L.) Merr.] plays a critical role in global food security and sustainability, acquiring most of the nitrogen (N) required for growth and high-protein seeds from symbiotic N fixation (SNF). However, there is scarce information on how soil N supply interacts with N fixation (kg ha−1) throughout the growing season. This study aims to (1) evaluate the allometric relationships between the total N uptake and dry matter by N source (soil and fixation), (2) describe seasonal changes on soil-plant N dynamics among genotypes with contrasting genetic background (released between 1981 and 2019), and (3) assess the influence of soil NO 3 and NH 4 on the temporal SNF changes during the growing season. Four genotypes were field grown during 2019 and 2020. Bayesian non-linear models described seasonal change on dry matter, N uptake, soil NO 3 , and NH 4 (60 cm depth). The allometric relationship between N uptake and dry matter indicated that total N status is more sensitive to variations in N uptake from the soil than from fixation. Seasonal exposure to NH 4 (given by the area under the curve) and a delay on maximum NO 3 availability from early to mid-season suppressed end-season N fixation by two-fold the benefit on soil N uptake (kg ha−1). Both the magnitude and timing of soil N sources affected N uptake in all tested genotypes. Future research must explore broader SNF levels for understanding to what extent soil N can affect the N uptake sources, especially SNF, without decreasing seed yield in soybeans. • This study evaluates synchrony between in-season dynamics of soil N and SNF. • Allometric relationships indicate a stable balance between dry matter and N sources. • In-season soil ammonium exposure significantly reduced the end-season N fixation. • The in-season peak of nitrate decreased N fixation more than increased soil uptake. [ABSTRACT FROM AUTHOR]

Crop growth models can be useful tools to evaluate potential scenarios, yet the limited field data is an obstacle for providing significant insights at the local level. This certainly applies to several regions in Africa, where crop models built regional scenarios based on low resolution field data, leading to unsupported agricultural interventions on smallholders' systems. This review provides a synthesis analysis of crop modeling efforts in Africa using Agricultural Production Systems Simulator (APSIM) studies as a case-study. This research aims to highlight the value of standardized protocols to collect, store and deploy field data, and highlights the critical issue of limited data accessibility of published manuscripts and unavailability of a data sharing platform.Investment in local-level data collection and data sharing platforms is critical to guarantee the advancement of science and to provide reliable assessments to address complex challenges of food, nutrition, and climate security in Africa. [Display omitted] • Limited field data represents a challenge for crop models to provide useful insights. • This study showcases the need for investments on open data sources. • A systematic review was executed to collect crop modeling studies within Africa. • There is a need of standardization for field data collection and its accessibility. • Investment in local-level data is critical to provide reliable food assessments. [ABSTRACT FROM AUTHOR]

Tillering allows grass crops to adapt to their environment by increasing leaf area (source) and grain set (sink). Efficient translocation of water-soluble carbohydrates (WSCs) from tiller biomass is key to match the carbon (C) demand of ears. This ability is still commonly disputed, particularly in corn (Zea mays L.) when tillers are barren. Clarifying these points is imperative to determine tiller utility in corn crops, particularly when low plant densities are employed to manage restrictive environmental conditions with lower yield potential. Therefore, the objectives of the current study are to determine the following: 1) the impact of plant density and tiller presence on corn biomass accumulation, 2) the reproductive efficiency of tillered corn phenotypes considering the harvest index (grain to aboveground biomass ratio), and 3) the changes in stem C storage capacity and remobilization capabilities across tested environment × management scenarios. The database used to accomplish these objectives included six site-years across Kansas, United States; three plant densities (25,000, 42,000, and 60,000 plants ha−1); two genotypes (P0657AM and P0805AM); and two tiller scenarios (intact or removed at stage V10). At these site-years, aboveground biomass and stem samples for WSC were collected at five unique timepoints throughout the season. Tiller presence stabilized aboveground biomass across plant densities and increased the WSC storage capacity in the lowest plant density. Whole plant harvest index was maintained at approximately 0.49 regardless of tiller biomass. Results indicate corn tillers enhanced WSC storage and reduced sink limitations during grain fill in the environments sampled in this study (less water-restrictive conditions). Therefore, biomass and carbohydrate accumulation of tillered phenotypes accompanied the escape from yield dependence on plant density, as evidenced in previous publications from this database. While tillers were not directly responsible for yield efficiency reductions in tillered phenotypes with the environments and metrics evaluated in the current study, more resource-restrictive environments (with less water, for example) could alter this outcome. Additional work on the carbon economy of tillered corn plants in more diverse environments is needed. • Corn tillers provided stability to aboveground biomass production across plant densities. • Tiller biomass was not correlated with whole plant harvest index values. • Tillers provided an additional source of carbohydrates for developing ears. [ABSTRACT FROM AUTHOR]

Global climate models predict increase in mean daily temperature to be mainly driven by rapid increase in nighttime temperature compared to daytime temperature, leading to narrowing diurnal temperature amplitude. Higher day and night temperatures induce significant negative impact on growth and development of different crops. However, limited studies have focused on quantifying impacts associated with different diurnal temperature amplitudes maintaining the same daily mean temperature. The main objectives were to (i) quantify the impact of diurnal temperature amplitudes on the carbon balance of the plant (photosynthesis versus night respiration rate) and (ii) evaluate the significance of variable day and night temperature with a common mean on the carbohydrate composition and overall plant growth. A maize hybrid (DKC47-27RIB) was grown in controlled environments at two mean daily temperatures (30 °C and 35 °C) with three different combinations of day and night temperatures resulting in diurnal temperature amplitudes of 2 °C, 10 °C and 18 °C. After 42 days of temperature treatments, lower diurnal temperature amplitude led to a linear increase in night respiration and a linear decrease in total sugars, non-reducing sugars, starch concentrations, plant height, total leaf area and total biomass accumulation. However, there was no significant change in photosynthetic rate among the treatment combinations, while photochemical efficiency (Fv/Fm) and chlorophyll index decreased only with diurnal temperature amplitude of 18 °C and 2 °C, respectively. A significant negative relationship was found between night respiration and total biomass accumulation (R 2 = 0.73; P < 0.01 ), total leaf area (R 2 = 0.82; P < 0.01), specific leaf area (R 2 = 0.21; P < 0.01), non-reducing sugars (R 2 = 0.50; P < 0.01) and starch concentrations (R 2 = 0.50; P < 0.01). The results imply that narrowing diurnal temperature amplitude as a result of higher night temperature is the major driver of the negative impact on vegetative growth in maize. [ABSTRACT FROM AUTHOR]

Understanding how wheat ( Triticum aestivum L.) plants under high temperature (HT) regulate lipid composition is critical to developing climate-resilient varieties. We measured 165 glycerolipids and sterol derivatives under optimum and high day and night temperatures in wheat leaves using electrospray ionization-tandem mass spectrometry. Levels of polar lipid fatty acyl chain unsaturation were lower in both heat-tolerant genotype Ventnor and susceptible genotype Karl 92 under HT, compared with optimum temperature. The lower unsaturation was predominantly because of lower levels of 18:3 acyl chains and higher levels of 18:1 and 16:0 acyl chains. Levels of 18:3-containing triacylglycerols increased threefold/more under HT, consistent with their possible role in sequestering fatty acids during membrane lipid remodelling. Phospholipids containing odd-numbered or oxidized acyl chains accumulated in leaves under HT. Sterol glycosides (SG) and 16:0-acylated sterol glycosides (ASG) were higher under HT than optimum temperatures. Ventnor had lower amounts of phospholipids with oxidized acyl chains under HT and higher amounts of SG and 16:0-ASG than Karl 92. Taken together, the data demonstrate that wheat leaf lipid composition is altered by HT, in which some lipids are particularly responsive to HT, and that two wheat genotypes, chosen for their differing physiological responses to HT, differ in lipid profile under HT. [ABSTRACT FROM AUTHOR]

Including winter canola (Brassica napus L.) crop into cereal-based crop rotations can diversify the current agricultural systems in the United States (US). In addition, canola can help to satisfy market demand for plant-based edible oil, thus better understanding of oil productivity of canola in the US production areas is relevant for further study. Canola seed oil concentration is a function of the genotype (G), environment (E), management (M), and their interaction (G × E × M). The overall aim of this research study was to identify suitable production environments with increased canola seed oil concentration and opportunities to increase cropland area in the US. The objectives of this research were: i) characterize the environmental variability of seed oil concentration in the National Winter Canola Variety Trials (NWCVT), ii) identify geographical regions and states within the continental US with potential for production of winter canola with high seed oil concentration and the link with yield, and iii) explore the potential development of varieties with stable high seed oil concentration and high yield. In this study, the E component accounted for 75% of the total variation in seed oil concentration, with the G factor only explaining 8%. Overall, seed oil concentration averaged 398 g kg-1 but ranged from 311 to 461 g kg-1. The US Midwest and Great Plains regions were shown to have a greater frequency of medium (> 389 g kg-1) and high canola seed oil concentration (> 411 g kg-1). Genotypic variation for both seed oil concentration and yield was found with an opportunity to achieve high oil and yield under varying environments. Our findings suggests that there is significant potential to further expand the area of canola cropland to increase oil productivity and focus should be on breeding high yielding varieties with stable high seed oil concentration. • Environment explained most of the oil concentration variability in winter canola. • Precipitation and photothermal quotient explain the oil concentration variability. • Large winter canola production area with potential for high oil concentration in US. • Potential to develop varieties with stable high seed oil concentration and yield. [ABSTRACT FROM AUTHOR]

Pearl millet (Pennisetum glaucum R. Br.) water-limited yield gap in Senegal is estimated at 2.2 Mg ha-1. Proper variety and management selection are critical to the sustainable intensification of millet systems. The objectives of this study were to assess the effect of two pearl millet varieties and different crop management (plant density-nutrient rates) treatments on i) biomass yield, ii) grain yield, and iii) farm profit magnitude and responsiveness. The study was conducted on three sites during the 2017, 2018, and 2019 growing seasons with a total of nine site-years. Two varieties, Souna 3 (traditional) and Thialack 2 (dual-purpose), and 48 management treatments including two plant densities (37–74 × 1000 plants ha-1) and 24 different levels of nutrient combinations ranging from 0 to 149 kg ha-1 nitrogen (N, as urea), 0–67 kg ha-1 phosphorus (P 2 O 5 , as double super phosphate), 0–33 kg ha-1 potassium (K 2 O, as potassium chloride) and 0–14 987 kg ha-1 cow manure (M), were tested in all site-years. Thialack 2 presented greater biomass yield in three and grain yield in four site-years (out of nine site-years) relative to Souna 3. Management treatments with greatest magnitude and responsiveness produced on average 4.6 Mg ha-1 biomass yield with averaged nutrient rates of 102–37–26 NPK, 2 Mg ha-1 grain yield with averaged nutrient rates of 91–32–24 NPK, 682 USD ha-1 profit at low biomass and grain prices with averaged nutrient rates of 72–22–21 NPK, and 1183 USD ha-1 profit at high biomass and grain prices with averaged nutrient rates of 83–29–22 NPK, all at 74 thousand plants ha-1, regardless of variety used. Five to seven management practices were able to concurrently optimized biomass yield, grain yield, and farmer profit. Sustainably intensifying pearl millet systems by using improved variety and management practices have great potential to promote greater yields and farm profitability in Senegal. • New pearl millet varieties can be used for biomass and grain production. • Yield response and magnitude is driven by environmental conditions. • Greater plant density and nutrient application rates improve pearl millet yield. • Farm profit can be optimized with greater plant density and modest nutrient rates. • Pearl millet in Senegal has potential to be profitably intensified. [ABSTRACT FROM AUTHOR]

Soil salinity is the main environmental limiting factor for current agricultural farming systems in the Bangladesh coastal zone. Targeting crop selection to ameliorate its impact in food production is a priority to ensure food security, diversifying crop outputs and reducing smallholders' vulnerabilities. In this context, crop growth modelling emerges as a useful tool for exploring different scenarios for crop selection. Studying spatial and -temporal heterogeneity in salinity and crop productivity under different climate scenarios. A dataset from the Polder 30 located in the Bangladesh southwest coastal zone, including different farming systems (rice-maize, rice-mungbean, rice-sunflower) comprising two years (2017–2019), was utilized, together with polder-level contiguous layers of factors (i.e., salinity, elevation, precipitation), to create clusters representing different yield-limiting conditions. Two salinity scenarios were defined and included in a long term in-silico assessment to explore dry-season field crop options (maize, sunflower, and mungbean). APSIM models for maize, sunflower and mungbean, were selected to perform all the crop simulations. Based on yield, sunflower was the most stable choice under salinity and maize was the best under non-saline conditions. Lastly, yield stability was accounted for different climate conditions, showing a large yield reduction for maize when combining low precipitation and high temperature, whereas mungbean and sunflower presented less sensitivity to different climates. Right crop selection for the right environment, considering both salinity restrictions and climate uncertainties, is critical for long-term yield stability. The present study provides a novel framework to better match the most suitable crop under challenging salinity restrictions and climate uncertainties affecting smallholders in the coastal zone of Bangladesh. [Display omitted] • Targeting crop selection to optimize food production strengthens food security. • Spatial and temporal variability caused by salinity should be considered to aid smallholders to improve crop selection during the dry-season. • In-silico assessment with APSIM model indicates sunflower as a good choice for the dry-season under salinity and the projected climates. • Crop selection for the right environment is critical for long-term yield stability. • A new framework is provided to better match the most suitable crop under salinity restrictions and climate uncertainties. [ABSTRACT FROM AUTHOR]

Legumes play a key role in the sustainable intensification of agricultural systems, improving biodiversity, ecosystem services, and reducing the dependency of food production on nitrogen (N) fertilizers. This review aims to: (i) quantify seed yield per kg of total aboveground N and fixed aboveground N, (ii) study the N derived from the atmosphere (Ndfa) (as the slope of fixed aboveground N-to-total aboveground N relationship) and its potential, and (iii) estimate the partial N balance and the impact of belowground N on the net contribution of fixed N after seed harvest. We retrieved 83 studies (n = 889 data points) investigating biological N fixation, spanning from 1982 to 2020, and focusing on blue lupin (Lupinus angustifolius L.), chickpea (Cicer arietinum L.), common bean (Phaseolus vulgaris L.), cowpea (Vigna unguiculata (L.) Walp), faba bean (Vicia faba L.), field pea (Pisum sativum L.), groundnut (Arachis hypogaea L.), lentil (Lens culinaris Medik) and white lupin (Lupinus albus L.). The overall Ndfa did not change across legumes (0.84 kg fixed aboveground N kg total aboveground N-1), except for common bean (0.57 kg fixed aboveground N kg total aboveground N-1). In addition, common bean showed the lowest potential for the Ndfa (0.95 quantile slope), with the largest N-gap between potential and mean N fixation (0.5 quantile slope). The straw N concentration (r2 = 0.47) was the main contributor to the variation in the partial N balance. The incorporation of the belowground N to estimate overall N balance showed that this fraction is a key component to study the role of legumes in maintaining soil N fertility in agricultural systems. Future studies should accurately quantify both above- and below-ground contribution to N fixation process in order to improve the estimation of field N balances in legume-based systems. • Legumes did not differ on their average to fix N, except for common bean. • Common bean had the largest N-gap between potential and mean N fixation. • White lupin showed the largest shift when roots were included into the N balance. • The partial N balance was highly variable, but greatly dependent on straw N concentration. [ABSTRACT FROM AUTHOR]

Highlights: [•] Climate change is predicted to decrease sorghum yield at sites in India and Mali. [•] Longer crop maturity duration increased the yield of sorghum under climate change. [•] Enhanced yield potential traits increased the yield at all the sites. [•] Drought and heat tolerance traits in sorghum increased the yield at most sites. [•] CERES-sorghum model was useful in quantifying the benefits of traits at the sites. [Copyright &y& Elsevier]

Abstract: Crop growth simulation models are a useful tool to assess the impact of environment, crop management, genetics and breeding strategies, as well as climate change and variability on growth and yield. Any crop science experiment that measures key physiological processes, tests these productive processes, their interaction with other processes, environment, and intra- and inter-specific variation, is valuable to inform and refine crop simulation models. This paper focuses on crop science experiments in three key areas—crop development, seed or fruit-set at high temperature, and water use—illustrating some of the experiments used to understand key processes and, equally importantly, quantify these processes for crop models in a robust and repeatable manner. One particularly useful experimental method for determining stages of development responsive to photoperiod and temperature (the main drivers of ontogenic development), and sensitive to abiotic stresses such as temperature extremes and water deficit, is transfer experiments between different environments or treatments. Once sensitive stages are defined, then responses and genotypic differences can be accurately quantified. Understanding and modeling transpiration, and particularly genotypic differences in processes affecting transpiration is also key process for crop modeling. Experiments to determine genotypic differences in soil water availability thresholds that control when transpiration is reduced, relations between transpiration and vapor pressure deficit (VPD), and patterns of soil water uptake are also described along with new insights from this work. One of the biggest constraints to improving models with crop science experiments—and exploiting advances in genomics—is the limited capacity to phenotype traits and physiological mechanisms. Most crop science experiments have quantified responses in only a limited number of genotypes and the diversity of genotypic responses is not well represented. Today there is an increased demand for good quality phenotyping which can serve both genomics and modeling, and there is an urgent need to re-invest in crop physiology for high quality phenotyping. [Copyright &y& Elsevier]

The COVID-19 pandemic has been affecting health and economies across the world, although the nature of direct and indirect effects on Asian agrifood systems and food security has not yet been well understood. This paper assesses the initial responses of major farming and food systems to COVID-19 in 25 Asian countries, and considers the implications for resilience, food and nutrition security and recovery policies by the governments. A conceptual systems model was specified including key pathways linking the direct and indirect effects of COVID-19 to the resilience and performance of the four principal Asian farming and food systems, viz, lowland rice based; irrigated wheat based; hill mixed; and dryland mixed systems. Based on this framework, a systematic survey of 2504 key informants (4% policy makers, 6% researchers or University staff, 6% extension workers, 65% farmers, and 19% others) in 20 Asian countries was conducted and the results assessed and analysed. The principal Asian farming and food systems were moderately resilient to COVID-19, reinforced by government policies in many countries that prioritized food availability and affordability. Rural livelihoods and food security were affected primarily because of disruptions to local labour markets (especially for off-farm work), farm produce markets (notably for perishable foods) and input supply chains (i.e., seeds and fertilisers). The overall effects on system performance were most severe in the irrigated wheat based system and least severe in the hill mixed system, associated in the latter case with greater resilience and diversification and less dependence on external inputs and long market chains. Farming and food systems' resilience and sustainability are critical considerations for recovery policies and programmes, especially in relation to economic performance that initially recovered more slowly than productivity, natural resources status and social capital. Overall, the resilience of Asian farming and food systems was strong because of inherent systems characteristics reinforced by public policies that prioritized staple food production and distribution as well as complementary welfare programmes. With the substantial risks to plant- and animal-sourced food supplies from future zoonoses and the institutional vulnerabilities revealed by COVID-19, efforts to improve resilience should be central to recovery programmes. This study was the first Asia-wide systems assessment of the effects of COVID-19 on agriculture and food systems, differentiating the effects of the pandemic across the four principal regional farming and food systems in the region. Notes: Full lines denote direct effects; dashed lines indirect effects; and thickness of line denotes relative strength of effects. [Display omitted] • This regional synthesis addresses a major gap in knowledge about the effects of COVID-19 on agriculture and food across Asia • Key informants from 20 Asian countries assessed early direct and indirect effects on each of four major regional farming and food systems • The analysis showed Asian farming and food systems were moderately resilient to the pandemic, especially the hill mixed system • System resilience, food and labour markets, and farm and food chain economic benefits are key priorities for recovery policies and programmes • This study highlights COVID-19 effects and informs recovery policies and precautionary strategies against future pandemics in Asia and globally [ABSTRACT FROM AUTHOR]

Cultivars with efficient root systems play a major role in enhancing resource use efficiency, particularly water absorption, and thus in drought tolerance. In this study, a diverse wheat association panel of 136 wheat accessions including mini core subset was genotyped using Axiom 35k Breeders' Array to identify genomic regions associated with seedling stage root architecture and shoot traits using multi-locus genome-wide association studies (ML-GWAS). The association panel revealed a wide variation of 1.5- to 50-fold and were grouped into six clusters based on 15 traits. Six different ML-GWAS models revealed 456 significant quantitative trait nucleotides (QTNs) for various traits with phenotypic variance in the range of 0.12–38.60%. Of these, 87 QTNs were repeatedly detected by two or more models and were considered reliable genomic regions for the respective traits. Among these QTNs, eleven were associated with average diameter and nine each for second order lateral root number (SOLRN), root volume (RV) and root length density (RLD). A total of eleven genomic regions were pleiotropic and each controlled two or three traits. Some important candidate genes such as Formin homology 1, Ubiquitin-like domain superfamily and ATP-dependent 6-phosphofructokinase were identified from the associated genomic regions. The genomic regions/genes identified in this study could potentially be targeted for improving root traits and drought tolerance in wheat. [ABSTRACT FROM AUTHOR]

The global COVID-19 pandemic has produced a variety of unanticipated shocks to farming and socio-economic systems around the world. In case of Senegal, the country was already facing number of challenges at the inception of the pandemic, including high rates of poverty, prevalence of food insecurity, combined with other biophysical and socioeconomic challenges faced generally in Sub-Saharan Africa. To understand farmer perceptions of the potential impacts of COVID-19 on agricultural systems and social well-being of smallholder farmers in Senegal. Particular attention was given to potential vulnerabilities and resilience in the targeted farming systems. A survey was developed to better understand smallholder farmer perceptions regarding the anticipated impacts of COVID-19 on their agriculture practices and social well-being. The survey was administered (between June 5 and June 20) with smallholder farmers (n = 872) in 14 regions covering all agroecological zones. Variables of interest included perceptions of potential impact on farming systems, agricultural productivity, communities, economics, markets, labor, gendered division of labor, food security, and community well-being. Across the three farming systems examined (cropping, livestock, and horticulture) significant majorities expressed concerns related to access to inputs, ability to plant (cropping, horticulture), reduction of yields (cropping, horticulture), ability to feed livestock, ability to sell livestock, and the ability to hire labor (horticulture). The majority of respondents also expressed concern that COVID-19 would make it more difficult to get enough food on a regular basis for their household (82.5%); that the markets where they purchase food will either be closed or significantly disrupted (79.5%); that the price of food would increase (73.5%); and the market where they sell their produce/livestock will be either closed or significantly disrupted (73.2%). Anticipated impacts of COVID-19 on agriculture will be felt on both the biophysical aspects such as production and access to inputs and socioeconomic aspects such as access to labor, markets, or rapid shifts in demand. Results support the need to use farming systems approach to gather perceived and actual impacts of COVID-19 and warrants a more in-depth examination of agronomic and biophysical issues as well as the impact on the livelihoods and social well-being of families at community and household levels. Further examination will help identify the characteristics that strengthen smallholder farming systems resilience to adjust to anticipated and unanticipated shocks, such as COVID-19, to decrease the negative impacts and increase the rate of recovery. [Display omitted] • Farmers perceptions on impact of COVID-19 on food systems in Senegal was quantified. • Respondents included 872 farmers from 14 regions across all agroecological regions. • Inputs, planting and yields of crops, managing livestock, labor were key concerns. • Disruption and access to market for selling and purchasing food is expected. • Food availability on a regular basis for their household will be major problem. [ABSTRACT FROM AUTHOR]

Diversifying and intensifying the rice-based cropping systems in the southern coastal zone of Bangladesh is a government priority to meet the food, feed, and fiber demand of an increasing population and changing climate. This study was conducted for three years (2016–2019) in Polder 30 located in southwest coastal zone of Bangladesh with five cropping systems [improved varieties of rice-maize (R-M); rice-mungbean (R-MB); rice-sunflower (R-S); traditional varieties of rice-mungbean (R Trad -MB Trad); and rice-fallow (R Trad -F)]. The objectives were to quantify yield gaps and spatiotemporal variability in rice production, evaluate various rice-based cropping systems for yield and profitability, and investigate individual crop and system-based stability and resilience in the coastal zone. Averaged over three years, results indicated an approximate 30% attainable yield gap on average within improved varieties and a 56% yield difference between traditional and improved rice varieties. Spatial autocorrelation analysis of both systems was positive and significant, suggesting crop yields in spatially closer locations were similar than those that were far apart. Lower spatial autocorrelation for the improved variety of rice compared to traditional varieties, indicates greater spatial dependence in addition to a narrow yield range for traditional rice. Overall, the improved rice-maize and rice-sunflower systems were the highest yielding and productive cropping systems, followed by the improved rice-mungbean. The traditional rice-fallow system was the least productive. In a high climate-risk year, however, rice was the only crop with positive net income, and the traditional systems had a relatively higher income than the improved systems. In an average opportune year, maize had the highest net income, and all improved rice-based cropping systems had a relatively higher income than traditional systems. • Large attainable rice yield gaps (30% within improved varieties) exist in the polders. • Traditional varieties of rice have more spatial dependence and narrow yield range. • Rice-Maize and Rice-Sunflower systems had highest rice equivalent yield. • The traditional systems had higher income than the improved systems under harsh climatic conditions. [ABSTRACT FROM AUTHOR]

Sorghum is an important crop that serve multiple purposes as human food, animal feed, and bioenergy production. There are opportunities to produce different types of biofuels from sorghum-based biomass. Sorghum with its vast genetic resources can serve as bioenergy crop and not compete against the value of it as food and nutritional security crop. Bioenegy crops provides an opportunity for agriculture to be part of solution for energy and mitigation to climate change. This review provides detailed overview and current knowledge on the conversion of sorghum biomass (stalks, leaves, and grains) into liquid (bioethanol, biodiesel, and bio-oil), gas (biohydrogen, biogas, and syngas) and solid (biochar) biofuels. Progress made in the different sorghum-based biomass pretreatment and conversion processes including chemical, biochemical, thermochemical and biological processes (e.g. saccharification, fermentation, transesterification, hydrothermal liquefaction, pyrolysis, and gasification) are highlighted and described. In addition, several value-added products from sorghum gaining importance in biofuels production are summarized. Finally, the potential outlook on sorghum based biorefiners and potential for improving sorghum-based biofuel production is presented and discussed. The biorefinery concept offers a considerable scope for optimization of sorghum biomass utilization to produce biofuels and biochemicals. However, there is further need to clearly identify the best methods of pre-treatment, processing, and products from different sources. Sorghum with its high biomass production and multiple use has the potential to be key biofuel crop. Further research is needed to identify most efficient and cost effective processes to ensure the value of biofuel and other bioproducts from sorghum. A complete lifecycle analyses indicating the challenges and opportunities to enhance the efficiency, benefits, and challenges in different steps and finding solutions to overcome those challenges will be of prime importance. Strong collaboration between private and public sector researhcers and multidisciplinary teams will be required to develop a comprehensive biorefinery models. Overview of various methods of biofuel production from sorghum. Image 1 • Reviews current knowledge on various methods for biofuel production from sorghum. • Sorghum oil, germ and dried grains with solubles are viable biodiesel feedstocks. • Commercialization of thermochemical processes is more reliable than biological ones. • Biologists should optimize the sorghum biomass properties for biofuel production. • Biorefinery concept offers a scope for optimization of sorghum biomass utilization. [ABSTRACT FROM AUTHOR]