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The developmental transition from vegetative to reproductive growth stage is highly sensitive to drought stress in corn (Zea mays L.). Understanding the physiological responses of corn to withstand and recover from drought during early reproductive development is crucial for ensuring stable yields. Therefore, the present study assessed the effects of short-term (7 days) drought stress on the physiology of corn and its ability to recover during the pre-anthesis, mid-silking, and blistering stages. Furthermore, the study examined the effect of drought stress on kernel yield and quality. On average, drought stress during the tasseling, mid-silking, and blistering stages significantly reduced stomatal conductance (82%) and transpiration (81%). These changes under drought led to an average increase in leaf temperature by 3 [degrees]C compared to the control. Leaf chlorophyll content declined by 46% and did not recover after rewatering. Unlike pigments, canopy temperature and quantum efficiency of photosystem II showed substantial recovery after rewatering across growth stages. Drought stress during mid-silking and blistering led to a significant decline of kernel weight by 33% and 34% compared to the control. Average kernel starch was 65%, and protein was 11% across treatments, reflecting kernel quality. Compared with control, drought stress during tasseling led to significant yield losses followed by mid-silking and blistering. The study highlights the importance of managing drought stress by maintaining optimum irrigation around pre- and post-anthesis plant health and efficient kernel set in corn. Keywords: Blistering, Corn, Drought, Physiology, Quality, Tasseling, Mid-silking, Yield., INTRODUCTION Corn, a major annual monoecious crop, requires a substantial amount of water, with a footprint of 1,222 L, to produce one kg of kernels (Mekonnen and Gerbens-Leenes, 2020; Erenstein [...]

Highlights: This review presents a summary of the literature on the effects of elevated CO2 and temperature on grain legumes Fertilization effect of elevated CO2 has a positive effect on photosynthesis and biomass growth Grain nutrition content of grain legumes can decrease Pollinators' visits to flowering plants can be higher, enhancing pollination Carbon dioxide (CO2) is the most abundant greenhouse gas (GHG) in the atmosphere and the substrate for the photosynthetic fixation of carbohydrates in plants. Increasing GHGs from anthropogenic emissions is warming the Earth's atmospheric system at an alarming rate and changing its climate, which can affect photosynthesis and other biochemical reactions in crop plants favorably or unfavorably, depending on plant species. For the substrate role in plant carbon reduction reactions, CO2 concentration ([CO2]) in air potentially enhances photosynthesis. However, N uptake and availability for protein synthesis can be a potential limiting factor in enhanced biomass synthesis under enriched [CO2] conditions across species. Legumes are C3 plants and symbiotic N fixers and are expected to benefit from enhanced [CO2] in the air. However, the concurrent increase in air temperatures with enhanced [CO2] demands more detailed investigations on the effects of [CO2] enhancement on grain legume growth and yield. In this article, we critically reviewed and presented the online literature on growth, phenology, photosynthetic rate, stomatal conductance, productivity, soil health, and insect behavior under elevated [CO2] and temperature conditions. The review revealed that specific leaf weight, pod weight, and nodule number and weight increased significantly under elevated [CO2] of up to 750 ppm. Under elevated [CO2], two mechanisms that were affected were the photosynthesis rate (increased) and stomatal conductivity (decreased), which helped enhance water use efficiency in the C3 legume plants to achieve higher yields. Exposure of legumes to elevated levels of [CO2] when water stressed resulted in an increase of 58% in [CO2] uptake, 73% in transpiration efficiency, and 41% in rubisco carboxylation and decreased stomatal conductance by 15–30%. The elevated [CO2] enhanced the yields of soybean by 10–101%, peanut by 28–39%, mung bean by 20–28%, chickpea by 26–31%, and pigeon pea by 31–38% over ambient [CO2]. However, seed nutritional qualities like protein, Zn, and Ca were significantly decreased. Increased soil temperatures stimulate microbial activity, spiking organic matter decomposition rates and nutrient release into the soil system. Elevated temperatures impact insect behavior through higher plant feeding rates, posing an enhanced risk of invasive pest attacks in legumes. However, further investigations on the potential interaction effects of elevated [CO2] and temperatures and extreme climate events on growth, seed yields and nutritional qualities, soil health, and insect behavior are required to develop climate-resilient management practices through the development of novel genotypes, irrigation technologies, and fertilizer management for sustainable legume production systems. [ABSTRACT FROM AUTHOR]

Introduction: Environmental conditions play a prime role in the growth and development of plant species, exerting a significant influence on their reproductive capacity. Soybean is sensitive to high temperatures during flowering and seed developmental stages. Little is known about the combined environmental effect of temperature and CO2 on seed yield and quality and its future generation. Methods: A study was conducted to examine the effect of temperature (22/14°C (low), 30/22°C (optimum), and 38/30°C (high)), and CO2 (420 ppm (ambient; aCO2) and 720 ppm (elevated; eCO2)) on seed yield, quality, and transgenerational seedling vigor traits of soybean cultivars (DS25-1 and DS31-243) using Soil-Plant-Atmospheric-Research facility. Results: A significant temperature effect was recorded among yield and quality attributes. At high-temperature, the 100-seed weights of DS25-1 and DS31-243 declined by 40% and 24%, respectively, over the optimum temperature at aCO2. The harvest index of varieties reduced by 70% when exposed to high temperature under both aCO2 and eCO2, compared to the optimum temperature at aCO2. The seed oil (- 2%) and protein (8%) content altered when developed under high temperature under aCO2. Maximum sucrose (7.5%) and stachyose (3.8%) accumulation in seeds were observed when developed under low temperatures and eCO2. When the growing temperature increased from optimum to high, the seed oleic acids increased (63%), while linoleic and linolenic acids decreased (- 28% and - 43%, respectively). Significant temperature and CO2 effects were observed in progenies with the highest maximum seedling emergence (80%), lesser time to 50% emergence (5.5 days), and higher seedling vigor from parents grown at low-temperature treatment under eCO2. Discussion: Exposure of plants to 38/30°C was detrimental to soybean seed yield, and eCO2 levels did not compensate for this yield loss. The high temperature during seed developmental stages altered the chemical composition of the seed, leading to an increased content of monounsaturated fatty acids. The findings suggest that parental stress can significantly impact the development of offspring, indicating that epigenetic regulation or memory repose may be at play. [ABSTRACT FROM AUTHOR]

Cotton is a pivotal global commodity underscored by its economic value and widespread use. In the face of climate change, breeding resilient cultivars for variable environmental conditions becomes increasingly essential. However, the process of phenotyping, crucial to breeding programs, is often viewed as a bottleneck due to the inefficiency of traditional, low-throughput methods. To address this limitation, this study utilizes hyperspectral remote sensing, a promising tool for assessing crucial crop traits across forty cotton varieties. The results from this study demonstrated the effectiveness of four vegetation indices (VIs) in evaluating these varieties for water-use efficiency (WUE). The prediction accuracy for WUE through VIs such as the simple ratio water index (SRWI) and normalized difference water index (NDWI) was higher (up to R2 = 0.66), enabling better detection of phenotypic variations (p < 0.05) among the varieties compared to physiological-related traits (from R2 = 0.21 to R2 = 0.42), with high repeatability and a low RMSE. These VIs also showed high Pearson correlations with WUE (up to r = 0.81) and yield-related traits (up to r = 0.63). We also selected high-performing varieties based on the VIs, WUE, and fiber quality traits. This study demonstrated that the hyperspectral-based proximal sensing approach helps rapidly assess the in-season performance of varieties for imperative traits and aids in precise breeding decisions. [ABSTRACT FROM AUTHOR]

Potassium (K) deficiency in corn is an emerging concern, especially when the crop is exposed to stress conditions. The insufficient replenishment of K in soil heightens the severity. A good K management requires adequate knowledge of its effect on plant growth and physiology. A sunlit growth chamber study was conducted under five levels of potassium concentrations, 100% (control; 193 ppm), 40%, 20%, 5%, and 0%, using modified Hoagland's nutrient solution applied at first leaf stage and continued until tasseling. The plant growth and development were monitored at different growth stages. Physiological parameters were measured at the tasseling stage. Significant differences (p < 0.05 to 0.001) in plant growth and physiological parameters were recorded in response to potassium rates. The 0% K treatment reduced the leaf K content and addition of leaf area day−1 by 85% and 8%, respectively, compared to the control. The rate of total biomass accumulation reduced to 5.4 g day−1 under 0% K compared to 7.7 g day−1 under the control. The root-to-shoot ratio increased to 0.33 at 5% K compared to 0.16 at the control treatment. The photosynthetic rate was reduced by 30% and 35% under 5% and 0% potassium concentrations, respectively, compared to the control. The 0% K deficiency decreased the stomatal conductance by 60% over control, lowering the internal CO2 level and transpiration. Linear and quadratic relationships were observed between leaf K content and electron transport rate (R2 = 0.98) and transpiration rate (R2 = 0.96), respectively. The functional relationships generated from this study will help improve corn models for field applications. [ABSTRACT FROM AUTHOR]

Planting crops in alternative row patterns such as skip row, twin-row, or narrow-row, in comparison to a conventional 102-cm single row pattern, has been shown to increase root spacing, canopy closure, and yields. Two studies were conducted to assess the effect of alternative row patterns on fiber properties. The objective of the first study was to compare fiber properties for cotton in narrowrow (38-cm solid) and twin-row (25-cm paired on 102-cm beds) at different plant populations to conventional 102-cm solid rows at standard plant population. The objective of the second study was to compare fiber properties for cotton in twin-row (38-cm paired on 102-cm beds) to conventional 102-cm solid rows. In the first study, cotton was planted two years in both non-irrigated and irrigated fields near Stoneville, MS. Each field included the same eleven treatments: 38-cm solid and 25-cm paired rows at five plant populations and 102-cm rows at standard plant population. In the second study, two varieties were each planted two years in an irrigated field near Stoneville, MS. Lint quality samples in both studies were hand-picked from plots, ginned on a 10-saw gin stand, and analyzed by High Volume Instrument (HVI) and Advanced Fiber Information System (AFIS). In the first study, plant populations in the non-irrigated experiment ranged from 106,000 to 215,000 plants/ha in 38-cm rows; 99,000 to 217,000 plants/ha in 25- cm paired rows; and 126,000 plants/ha in 102-cm rows. Plant populations in the irrigated experiment ranged from 93,000 to 220,000 plants/ha in 38-cm rows; 90,000 to 194,000 plants/ha in 25-cm paired rows; and 127,000 plants/ha in 102-cm rows. No meaningful significant differences were found for HVI fiber properties (length, micronaire, strength, uniformity, reflectance, yellowness, or trash) or AFIS fiber properties (upper quartile length, short fiber content, nep count, seed coat nep count, fineness, immature fiber content, or maturity ratio) in comparing 38-cm solid or 25-cm paired rows to 102-cm solid rows in either non-irrigated or irrigated experiments. In the second study, fiber quality analysis showed fewer neps in the 38-cm twin rows. Other properties were favorable for 38- cm twin rows but not consistent for the two years or two varieties tested. The results of fiber quality demonstrate that cotton produced in 38-cm solid and 38-cm twin rows on 102-cm beds was equal to or better than cotton produced in conventional 102-cm rows. [ABSTRACT FROM AUTHOR]

Drought stress during the reproductive stage and declining soybean yield potential raise concerns about yield loss and economic return. In this study, ten cultivars were characterized for 20 traits to identify reproductive stage (R1–R6) drought-tolerant soybean. Drought stress resulted in a marked reduction (17%) in pollen germination. The reduced stomatal conductance coupled with high canopy temperature resulted in reduced seed number (45%) and seed weight (35%). Drought stress followed by rehydration increased the hundred seed weight at the compensation of seed number. Further, soybean oil decreased, protein increased, and cultivars responded differently under drought compared to control. In general, cultivars with high tolerance scores for yield displayed lower tolerance scores for quality content and vice versa. Among ten cultivars, LS5009XS and G4620RX showed maximum stress tolerance scores for seed number and seed weight. The observed variability in leaf reflectance properties and their relationship with physiological or yield components suggested that leaf-level sensing information can be used for differentiating drought-sensitive soybean cultivars from tolerant ones. The study led to the identification of drought-resilient cultivars/promising traits which can be exploited in breeding to develop multi-stress tolerant cultivars. [ABSTRACT FROM AUTHOR]

Addressing the challenges of dwindling groundwater resources and ever-increasing demands for water necessitate enhancing water use efficiency (WUE) in irrigated agriculture. In a 2-year study, we examined the effects of different levels of irrigation and PG on lint yield and WUE of furrow irrigated cotton in a Dundee silt loam in the Mississippi Delta. The main plots were three irrigation regimes: irrigating every furrow (FI), alternate furrow (HI), and no irrigation (RF) and subplots were two planting geometries (PG): single-row (SR) and twin-row (TR). Across FI and HI no significant differences were observed in plant height and biomass yield at flowering, but chlorophyll content index and leaf area index (LAI) were positively affected. Canopy closure in TR planting occurred earlier than SR leading to higher leaf areas available for harvesting more light during photosynthesis. Averaged across the irrigation regimes, the TR planting enhanced lint yield by 10.6% in 2018 and 17.6% in 2019 compared to SR. The average lint yield in SR and TR were: 1779 and 2028 kg ha-1 under FI, 1803 and 2082 kg ha-1 under HI, and 1573 and 1788 kg ha-1 under RF treatments, respectively. In FI and HI treatments, TR had higher lint yield than RF treatment by 13.8% and 16.5%, respectively. Lint yield in HI with TR had the highest irrigation WUE (3.4 kg ha-1 mm-1) followed by HI with SR (2.7 kg ha-1 mm-1). These results demonstrated that cotton grown in TR with HI could reduce irrigation water demand in silt loams. [ABSTRACT FROM AUTHOR]