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Corn (Zea mays L.) is a major irrigated crop in the Texas High Plains (THP). Inadequate precipitation, declining groundwater resources, and inevitable seasonal drought in the area have led to a greater number of studies on crop hybrids, water regimes, and other yield-enhancing techniques. A four-year field study was conducted to investigate the effect of foliar fungicide timing on corn grain yield, grain moisture, and grain test weight under different irrigation regimes. A fungicide containing QoI + DMI was applied to four to six corn hybrids each year at various growth stages (V5, R1, and V5 + R1). For all years, corn plants were grown under three irrigation regimes to meet the seasonal evapotranspiration (ET) requirements of 50% (I50), 75% (I75), and 100% (I100). Hybrid response to the timing of fungicide application and irrigation regime was not consistent over the years. However, in 2 of the 4 years, timing of fungicide application resulted in yield differences among the hybrids, especially at I75 and L100. For those years, the fungicide applied at R1 resulted in a higher grain yield, grain moisture, and grain test weight followed by the fungicide applied at V5 + R1. Results showed that hybrids reacted differently to the foliar fungicide based on the availability of water under disease-free conditions. This study further revealed that irrigation water could be reduced from I100 to I75 with a limited (5.6% in 2011, 11.3% in 2012, 1.3% in 2013, and 0.3% in 2014) yield penalty in the THP region. [ABSTRACT FROM AUTHOR]

The valorization of date palm wastes as bioresources has received little attention. In this context, the feasibility of date palm waste valorization through composting and the application effects on barley plants production under control condition was investigated. The principal requirements for compost to be safely used are stability and maturity that refer, respectively, to the microbial biomass activity's level, germination tests, and plant growth bioassays or phytotoxicity. Indeed, the phytotoxicity of composted date palm waste used for seed germination and seedling growth bioassays was researched. The finished compost values of the C/N ratio were 15.36 and 18.58%, 1.21%, 0.54%, and 0.95% for total organic carbon, N, P, and K contents, respectively. The concentration of heavy metals and microelements were lower and met the requirement established by national standards. Moreover, the end product was free from harmful pathogens like Salmonella, Escherichia coli, total coliforms, and fecal coliform bacteria. Application of compost extract (especially 25%, 50%, and 75%) did not affect barley seed germination, stimulated hypocotyl and radicle growth and is characterized by a GI exceeding 90%, demonstrating its stability and lack of phytotoxic effect. Moreover, compost promotes plant growth, improved physiological parameters, photosynthetic pigments, and plant biomass. According to the results, the prepared compost especially at the dose T3 (soil amended with 30 t/ha) increased the nutrients availability and uptake which may be the reason for an increase in photosynthetic activity, chlorophyll synthesis, and dry matter accumulation. Composting may well represent an acceptable solution for disposing of date palm waste and be of great interest to sustainable agriculture in Tunisia oasis ecosystems. [ABSTRACT FROM AUTHOR]

The developmental process of spike is critical for spike fertility through affecting floret primordia fate in wheat; however, the genetic regulation of this dynamic and complex developmental process remains unclear. Here, we conducted a high temporal‐resolution analysis of spike transcriptomes and monitored the number and morphology of floret primordia within spike. The development of all floret primordia in a spike was clearly separated into three distinct phases: differentiation, pre‐dimorphism and dimorphism. Notably, we identified that floret primordia with meiosis ability at the pre‐dimorphism phase usually develop into fertile floret primordia in the next dimorphism phase. Compared to control, increasing plant space treatment achieved the maximum increasement range (i.e., 50%) in number of fertile florets by accelerating spike development. The process of spike fertility improvement was directed by a continuous and dynamic regulatory network involved in transcription factor and genes interaction. This was based on the coordination of genes related to heat shock protein and jasmonic acid biosynthesis during differentiation phase, and genes related to lignin, anthocyanin and chlorophyll biosynthesis during dimorphism phase. The multi‐dimensional association with high temporal‐resolution approach reported here allows rapid identification of genetic resource for future breeding studies to realise the maximum spike fertility potential in more cereal crops. Summary statement: Floret primordia fates are determined by meiotic ability at the pre‐dimorphism phase: floret primordia with meiotic ability always develop into fertile florets, whereas meiotically incapable floret primordia usually abort. [ABSTRACT FROM AUTHOR]

Deficit irrigation (DI) is an effective way to save irrigation water while maintaining sustainable yield in irrigated crops. However, limited information is available related to canopy structure and solar radiation use under DI condition. In this study, our objective was to assess maize hybrids for leaf development, photosynthetically active radiation (PAR) interception and water use under DI condition. Field experiments were conducted in 2016 and 2017 in four maize hybrids at well‐watered (I100, referring to 100% evapotranspiration [ET] requirement) and DI (I75, referring to 75% ET requirement) water regimes. Compared to I100, I75 did not reduce maize biomass and grain yield. Although DI reduced the leaf appearance rates (1.5% in 2016 and 7.6% in 2017) and resulted in greater variations in leaf area index (LAI) among hybrids, the amount of PAR interception was not affected during the growing season. DI significantly reduced the seasonal ET in both years (19.8% in 2016 and 26.6% in 2017). All the hybrids extracted more soil water (29 mm in 2016 and 27 mm in 2017) at I75 than at I100. Maize plants at I75 had greater water use efficiency (WUE) (1.68 kg m−3) than those at I100 (1.41 kg m−3). However, DI did not affect radiation use efficiency (RUE). In conclusion, DI at I75 maintained grain yield through improved soil water extraction and WUE but stable canopy radiation interception and RUE. [ABSTRACT FROM AUTHOR]

In a semi‐arid climate, heat and drought stress can significantly reduce photosynthesis during grain filling hence, the remobilization of stored carbon reserves from stems becomes important to wheat (Triticum aestivum L.) yield. A 2‐year field study was conducted to better understand the contributions of different internodes to grain yield. We measured remobilization of stored carbon reserves in eight wheat genotypes under irrigated and dryland conditions. For each genotype, plant samples consisting of ten culms were collected between anthesis and physiological maturity. There was no difference in single stem weight loss between two water levels, but the stem loss contribution to yield was higher in dryland wheat (54.4%) than that in irrigated wheat (38.5%). Among the genotypes, the stem loss contribution to yield ranged 38.9%–58.1% in the relatively wet season of 2017 and 36.5%–62.5% in the dry season of 2018. The amount of stem loss showed a strong relationship with grain yield, especially under the dryland condition. At each sampling date, length as well as the dry weight of peduncle (first internode from the top) was greater than the other internodes; however, more stem loss (in weight and percentage weight) occurred in the third internode, followed by second and fourth internodes. Results suggest that the stem loss contribution to yield is greater under dryland than irrigated condition and occurs mainly in the middle portion of the culm. [ABSTRACT FROM AUTHOR]

Understanding transpiration efficiency (TE), especially in water-limited environments, is likely to result in increased crop yield. Two successive greenhouse experiments were conducted in 2017 to determine season-long TE in three corn (Zea mays L.) hybrids (P1151AM, 33D53AM, and P1564HR) and investigate whether the TE varies among different plant growth stages (six-leaf, flag leaf, mid-grain filling, and physiological maturity). Corn plants were grown in wooden boxes up to maturity while eliminating water loss except that lost in the form of transpiration. To prevent the belowground water loss, wooden boxes were lined with plastic sheets and sealed to the lids. The TE was determined as the ratio of aboveground biomass to cumulative water used in transpiration. The mean TE was the highest (6.27 kg m−3) when plants were harvested at the mid-grain-filling stage, followed by the flag leaf stage (5.91 kg m−3), and physiological maturity (5.81 kg m−3), and lowest at the six-leaf stage (5.25 kg m−3). Two-drought tolerant (DT) hybrids, P1151AM (6.20 kg m−3) and P1564HR (6.17 kg m−3), had higher TE than the conventional hybrid, 33D53AM (5.42 kg m−3). Grain-filling period is critical for water management in corn. This study showed that TE was also highest when plants were harvested at the mid-grain-filling stage and decreased thereafter. Therefore, producers, who have limited irrigation facilities, should develop a strategy to apply a sufficient amount of water before and during the grain-filling period for maximizing corn yield. [ABSTRACT FROM AUTHOR]