Maize requires more water than most other crops; therefore, the water use efficiency of this crop must be improved for maize production under undesirable land and changing environmental conditions. To elucidate the genetic control of drought in maize, we evaluated approximately 5000 inbred lines from 30 linkage-association joint mapping populations under two contrasting water regimes for seven drought-related traits, including yield and anthesis-silking interval (ASI). The joint linkage analysis was conducted to identify 220 quantitative trait loci (QTLs) under well-watered conditions and 169 QTLs under water-stressed conditions. The genome-wide association analysis identified 365 single nucleotide polymorphisms (SNPs) associated with drought-related traits, and these SNPs were located in 354 candidate genes. Fifty-two of these genes showed significant differential expression in the inbred line B73 under the well-watered and water-stressed conditions. In addition, genomic predictions suggested that the moderate-density SNPs obtained through genotyping-by-sequencing were able to make accurate predictions in the nested association mapping population for drought-related traits with moderate-to-high heritability under the water-stressed conditions. The results of the present study provide important information that can be used to understand the genetic basis of drought stress responses and facilitate the use of beneficial alleles for the improvement of drought tolerance in maize.

Maize (Zea mays L.) is a staple cereal crop worldwide, but its productivity is significantly affected by extreme weather conditions such as drought and heat stress. Plant growth, physiological processes, and yield potential are all affected by these conditions; as such, resilient maize crops are required to tackle these abiotic challenges. With an emphasis on morphological, physiological, and biochemical reactions, this review paper investigates the processes that underlie resistance to certain environmental challenges. Features including deep root systems, osmotic adaptations, and antioxidant enzyme activity help maize withstand drought. Activation of drought- and heat-responsive genes, accumulation of osmoregulatory compounds, and changes in membrane fluidity are all components of abiotic stress tolerance. Likewise, improved transpiration efficiency, modified photosynthetic processes, and improved heat shock proteins are used to produce heat resistance. Enhancing resilience requires progress in breeding methods, genetic engineering, and agronomic techniques, such as the use of stress-tolerant cultivars, biotechnology interventions, and climate-smart agriculture tactics. A special focus was given to cutting edge technologies like CRISPER-Cas9-mediated recent advances in heat and drought resistance. This review sheds light on recent studies and potential avenues for enhancing resilience to harsh climatic conditions, guaranteeing food security in the face of climate change.

As transcription factors derived from transposase, FAR-RED IMPAIRED RESPONSE1 (FAR1) and its homolog FHY3 play crucial roles in the regulation of light signaling and various stress responses by coordinating the expression of downstream target genes. Despite the extensive investigation of the FAR1/FHY3 family in Arabidopsis thaliana and other species, a comprehensive examination of these genes in maize has not been conducted thus far. In this study, we employed a genomic mining approach to identify 16 ZmFAR1 genes in the maize inbred line B73, which were further classified into five subgroups based on their phylogenetic relationships. The present study characterized the predicted polypeptide sequences, molecular weights, isoelectric points, chromosomal distribution, gene structure, conserved motifs, subcellular localizations, phylogenetic relationships, and cis-regulatory elements of all members belonging to the ZmFAR1 family. Furthermore, the tissue-specific expression of the 16 ZmFAR1 genes was analyzed using RNA-seq, and their expression patterns under far-red light conditions were validated in the ear and tassel through qRT-qPCR. The observed highly temporal and spatial expression patterns of these ZmFAR1 genes were likely associated with their specific functional capabilities under different light conditions. Further analysis revealed that six ZmFAR1 genes (ZmFAR1-1, ZmFAR1-10, ZmFAR1-11, ZmFAR1-12, ZmFAR1-14, and ZmFAR1-15) exhibited a response to simulated shading treatment and actively contributed to the development of maize ears. Through the integration of expression quantitative trait loci (eQTL) analyses and population genetics, we identified the presence of potential causal variations in ZmFAR1-14 and ZmFAR1-9, which play a crucial role in regulating the kernel row number and kernel volume weight, respectively. In summary, this study represents the initial identification and characterization of ZmFAR1 family members in maize, uncovering the functional variation in candidate regulatory genes associated with the improvement of significant agronomic traits during modern maize breeding.

Water is one of the most precious resources and is essential to agricultural output; the biggest user of water is the agricultural sector. Several societal sectors are impacted by the problem of climate change, including agriculture, water resources, and irrigation water demand. A key element in determining sustainable crop production potential is choosing the right cultivars at the right time of year to plant. The dates on which maize is sown are greatly impacted by high summer temperatures and low spring temperatures. Water stress and the timing of sowing can have a significant impact on maize crop yield and water use efficiency. As a result, figuring out the ideal irrigation volume and sowing dates depending on local conditions is essential. A split plot layout was used to create a randomized complete block design for an experiment with five sowing dates (A, B, C, D, and E) and six hybrids (KWS3376, Xinyu 65, KWS9384, Huamei No. 1, Xinyu 102, and Heyu 187). All sowing dates and hybrids had a significant impact on the yield and yield-contributing features (leaf length, ear diameter, grain number per spike, grain breadth, hundred-grain weight, etc.) of maize crops according to the data analysis. A higher grain yield with yield features, such as ear length, number of grains per ear, and hundred-grain weight, was obtained with early-season sowing. Delayed seeding resulted in a lower crop yield. The seasonally delayed seeding of maize reduces yield and yield characteristics. Xinyu 65 produced the highest yield and yield component values of any hybrid. For improved yield and yield traits in the examined area, the study recommended planting maize hybrid Xinyu 65 early in the growing season.

Leaf wilting is one of the most intuitive morphological manifestations of plants under drought stress, and it is useful in drought resistance screening. However, existing quantitative leaf-wilting measurement methods lack simplicity and high-throughput capacity under field conditions, and there is a gap in the systematic drought resistance assessments. The present study was conducted in 2020, 2021, and 2022 using 100 inbred maize lines. The maize lines were subjected to three different water stress treatments: normal irrigation, moderate drought, and severe drought. The findings led to the design of a simplified image acquisition and processing platform for measuring the visible green leaf area. A new measurement index and quantitative formula for wilting have been proposed, which effectively reflect leaf wilting and facilitate a systematic analysis of the relationship between yield and drought resistance. The results showed that the daily variation pattern of the visible green leaf area followed a trend of wilting first and then recovery, with maximum wilting occurring at noon (14:00–16:00 local time). The period of maximum wilting throughout the entire growth stage was the flowering stage. The maize plants with leaf wilt exceeding 1/2 (wilt ratio > 0.5) during the flowering stage were all low-yielding or low-tolerance inbred lines. In conclusion, this study emphasizes that the flowering stage is crucial for monitoring leaf wilting and introduces a quick high-throughput method to quantify leaf wilting. Our findings not only provide details about key indicators for identifying drought and heat resistance but also facilitate research on sustainable screening methods in maize, which will expedite the selection and accelerate the breeding of new varieties.

The agricultural sector faces significant challenges in maintaining crop productivity under environmental stressors such as drought and low nitrogen (LN) availability. Maize (Zea mays L.), a globally important cereal crop, is particularly vulnerable to these adverse conditions. We evaluated morphological data of 21 maize varieties under drought and low nitrogen. Results showed that vegetative traits showed moderate plasticity, while reproductive synchrony was the primary driver of yield stability. Drought stress led to a ~4-fold expansion of the Anthesis-Silking Interval (ASI), increasing from 0.14 to 0.55 days, which contributed to a 27% reduction in grain yield per plant (GYP). The network analysis showed that under drought, traits became fundamentally decoupled. In well-watered conditions, growth and yield formed a highly coordinated hub, but under water deficit the network fragmented — with tip blanking (r = –0.44) and empty kernel rate (r = –0.37) emerging as the key negative regulators. Conversely, the germplasm showed resilience to low nitrogen, with grain yield per plant (GYP) showing no significant difference from control (215 ± 19.3 g vs. 218 ± 21.5 g; P > 0.05). Under low nitrogen, kernel length (−2.1%, P < 0.05) and hundred-kernel weight (−3.2%, P < 0.05) decreased significantly, but total kernels per ear increased by 7.1% (P < 0.05), fully buffering yield through a sink-protected compensation strategy. Utilizing the Stress Tolerance Index (STI), we identified Xinyu 108, Ruipu 909, and Weike 702 as elite, multi-stress resilient varieties, highlighting their potential for cultivation in resource-limited environments. This research offers valuable insights for breeding programs focused on developing resilient maize varieties.