Aug 2026· Journal of Agronomy and Crop Science· Vol 212· 0 citations· 78 references
Abstract
Rising temperatures associated with climate change increasingly threaten cereal yields. Most previous studies have focused on chronic high temperatures, which primarily affect yield indirectly through modifications of crop phenology. In contrast, the effects of short‐term heat waves on reproductive development and yield formation remain poorly understood. In barley (
Hordeum vulgare
L.), development and reproduction are tightly regulated by photoperiod sensitivity, mainly controlled by the
PPD‐H1
gene, which may modulate plant responses to thermal stress. Here, we quantified the impact of a pre‐flowering heat wave on yield formation and spike fertility in near‐isogenic lines of spring barley differing at the
PPD‐H1
locus, across four contrasting environmental backgrounds combining sowing date and photoperiod conditions. Heat waves were imposed for 10 days at the flag leaf stage under field and outdoor conditions, increasing daily maximum temperatures with minimal effects on mean temperature and phenology. Across environments, the heat wave consistently reduced grain yield. Yield losses were primarily driven by reductions in grain number rather than grain weight and were markedly greater in the photoperiod‐insensitive
ppd‐H1
line than in the photoperiod‐sensitive
Ppd‐H1
line. Differences in flowering time between near‐isogenic lines were small or absent under most conditions, indicating that the contrasting heat wave responses were largely independent of phenological escape and instead reflected direct effects on reproductive development. The lower resilience of
ppd‐H1
was associated with both reduced floret fertility at flowering and increased grain abortion, particularly in apical spikelets, whereas spike fertility in
Ppd‐H1
plants was largely preserved. Our results demonstrate that the wild‐type
Ppd‐H1
allele confers enhanced tolerance to short‐term heat stress immediately before flowering by stabilising spike fertility and grain set. This study highlights the importance of photoperiod genes not only in shaping phenology but also in conferring intrinsic resilience of reproductive processes to heat waves, providing valuable insights for breeding barley cultivars adapted to increasingly variable thermal environments.
Heat stress is among the most critical abiotic constraints on cereal productivity, necessitating intensified breeding strategies. While elevated temperatures can occur at multiple developmental stages, heat stress during the post-anthesis period is particularly damaging, as it disrupts grain formation and filling, leading to substantial yield reductions. Although the study was conducted in a region traditionally favourable for barley cultivation, long-term meteorological records reveal a steady increase in post-anthesis temperatures over the past three decades, increasing crop vulnerability. Under these conditions, evaluating varietal performance and heat tolerance in line with current climatic trends is essential. In this study, chemical desiccation was applied to simulate heat stress by inhibiting photosynthesis, enabling assessment of the capacity of spring barley cultivars to remobilize assimilates from vegetative tissues to the grain. Ten cultivars were evaluated over three years under both stress and non-stress conditions, focusing on key yield components.
Emanuela Filip, C. Urdă, Matilda Ciucǎ et al.· Romanian Agricultural Resear...· 1 citation
It is demonstrated that subtle differences in developmental stage influence the complex molecular responses to heat and subsequent grain properties, including decoupling between the magnitude of responses and phenotypic outcomes.
Farhad Masoomi-Aladizgeh, T. Ashhurst, L. Quek et al.· bioRxiv· 0 citations
Future progress will depend on robust functional validation of key regulators, integration of multi-omics data with predictive breeding models, and broadening the genetic base of heat tolerance to sustain rice production under warming climates.
A. Saha, Aditya Pratap Singh, Debashis Paul et al.· Plant Molecular Biology Repo...· 0 citations
Context Barley production requires advanced knowledge of its response to changing environmental conditions in order to keep it competitive and sustainable. Aim Advance in the understanding of barley phenology and foliar development under South American field conditions. Methods 8 spring barley genotypes with differential phenology were studied in four field experiments under different temperature (through years and sowing dates) and photoperiod (through sowing dates) conditions. Time to anthesis, emergence to onset of stem elongation, stem elongation to anthesis, photoperiod response (PR) in these three traits, number of final leaves at anthesis (FLN) and phyllochron were measured. Key Results Time to anthesis and its subphases were shorter in late plantings but under similar photoperiod, temperature increased them. Cultivars have differential responses but with magnitude interactions and not crossover ones. Cultivar effects defined PR with no interaction with year (temperature). Temperature and photoperiod affected FLN, phyllochron and their relationship with time to anthesis. Under the shorter photoperiod, FLN and phyllochron were negatively correlated, FLN was higher in the warmer year and positively correlated with time to anthesis while phyllochron was not affected by temperature and had no correlation with time to anthesis. Under longer photoperiod, phyllochron was higher in the warmer year and time to anthesis was positively correlated with both FLN and phyllochron. Conclusions Cultivar basal thermal requirements and PR were consistent under the different studied conditions. Changes in temperature and photoperiod affected the relationship between time to anthesis, FLN and phyllochron suggesting that, although the three traits are arithmetically related, environmental conditions affect their balance. Online summary text Understanding barleýs responses to environmental changes are key for adapting the crop to future scenarios. Changes in temperature and photoperiod modify the crop final number of leaves, their rate of appearance, the length of the crop cycle and the interactions between these traits, implying important variations in the crop development. This information allows an improvement of crop practices in order to achieve a better crop and provides targets for breeding.
Nicolás Mastandrea, G. Quero, L. Viega et al.· bioRxiv· 0 citations
Climate change is exerting profound and multidimensional pressures on global wheat (
Triticum aestivum
L.) production. Rising temperatures, higher vapor pressure deficit, and more frequent heatwaves reduce yields through strong, phenology‐dependent effects, with flowering and grain filling identified as the most vulnerable stages. Compound heat–drought events disproportionately depress grain number and weight, while erratic precipitation marked by prolonged dry spells, intense rainfall, and waterlogging further destabilizes yield and degrades soil fertility. Meta‐analytic evidence shows wheat yield reductions exceeding 50% under drought and ∼23% under waterlogging, with associated declines in grain quality. Elevated CO
2
enhances photosynthesis and biomass in optimal conditions but fails to compensate for warming or drought and often lowers grain protein and mineral concentrations. Soil degradation, salinity, and nutrient imbalance are intensifying, while warming accelerates pest survival, reproduction, and geographic expansion, increasing biotic stress risks. Despite these challenges, multiple adaptation pathways demonstrate strong effectiveness. Drought‐tolerant cultivars, optimized sowing dates, deficit irrigation, mulching, conservation agriculture, and soil restorative practices significantly improve resilience. Precision agriculture, unmanned aerial vehicle remote sensing, Internet of Things‐enabled monitoring, and artificial intelligence (AI)‐driven decision‐support tools enhance early stress detection and management precision. Economic evidence consistently shows high returns from climate‐smart interventions. Strengthening policy coherence, climate‐informed services, and agricultural financing is essential to scale adaptation and secure wheat production under a warming climate.
Daniel Manore, Biruk Tagesse, Markos Makiso et al.· Agrosystems, Geosciences &am...· 1 citation
Mungbean is a nitrogen-fixing break crop in subtropical broadacre cereal rotation, yet how high nighttime temperatures (HNTs) threaten its agronomic contributions remain poorly characterized. A controlled environment (CE) experiment (low nighttime temperature, LNT: 20 °C vs. high nighttime temperature, HNT: 25 °C) and a two-year staggered-sowing field trial at Rockhampton, Queensland, evaluated HNT impacts on two genotypes, Jade AU and Green Dragon. In the CE experiment, HNT produced a strong, time-dependent increase in the respiration-to-photosynthesis (Rn/A) ratio, evident within two days of treatment imposition, compressed the pod-filling duration by 15%, and reduced grain yield by 21% through fewer mature pods without impairing individual grain filling. The sowing dates generated a contrasting combination of nighttime heat, daytime heat, solar radiation, and seasonal conditions. The harvest index was lower across the 2024 environments than the 2025 environments, but these year-level contrasts reflect co-varying thermal and radiation conditions rather than isolated HNT and High daytime temperature (HDT) environments. Although unadjusted Rn/A–grain yield associations differed between years, split-plot mixed models showed that Rn/A did not explain additional grain yield variation after accounting for sowing date, genotype, and experimental blocking structure. Therefore, Rn/A remains a candidate physiological response indicator, requiring further validation across broader germplasms and independently replicated environments. Green Dragon maintained a larger pod pool and showed less observed Rn/A than Jade AU in selected field environments. These traits identify Green Dragon as a promising source of reproductive resilience for further multi-environment evaluation. To align the reproductive phase with fewer warmer nights, sowing date management is the most accessible strategy for sustaining mungbean yield in subtropical broadacre cereal rotation systems under asymmetric warming.
