Kumar Hitesh, Chugh Vishal, Kumar Manoj, Gupta Vikas, Prasad Shambhoo, Kumar Satish, Singh Chandra Mohan, Kumar Rahul, Singh Bhupendra Kumar, Panwar Gurusharan, Kumar Mukul
Department of Genetics and Plant Breeding, College of Agriculture, Banda University of Agriculture and Technology, Banda, Uttar Pradesh, India.
Department of Basic and Social Sciences, College of Horticulture, Banda University of Agriculture and Technology, Banda, Uttar Pradesh, India.
Front Plant Sci. 2023 Aug 30;14:1189005. doi: 10.3389/fpls.2023.1189005. eCollection 2023.
Terminal heat stress has become one of the major threats due to global climate change which is significantly affecting the production and productivity of wheat crop. Therefore, it is necessary to identify key traits and genotypes to breed heat-tolerant wheat. The present study was undertaken with the objective of comparing the effects of heat stress (HSE) and extended heat stress (EHSE) on phenological-physio-biochemical traits of contrasting heat-tolerant and heat-susceptible genotypes during the reproductive phase. Phenological traits exhibited significant reduction under EHSE compared to HSE. Heat-tolerant genotypes maintained balanced phenological-physio-biochemical traits, while heat-sensitive genotypes showed significant reductions under both stress regimes. Among phenological traits, DM (R = 0.52) and BY (R = 0.44) have shown a positive effect on seed yield, indicating that biomass and crop duration contributed to the yield advantage under stress. During the grain filling stage, both the normalized difference vegetation index (NDVI) and chlorophyll (Chl) exhibited consistently positive impacts on grain yield under both HSE and EHSE conditions. This could be attributed to the enhanced photosynthesis resulting from delayed senescence and improved assimilate remobilization under terminal heat stress. The biochemical activity of superoxide dismutase (SOD), peroxidase (POX), and ascorbate peroxidase (APX) was induced in tolerant genotypes under HSE. The correlation of canopy temperature with phenological-physio-biochemical traits remained static under HSE and EHSE, suggesting CT as the best selection parameter for heat tolerance. The traits showing a positive association with yield and that are less affected under stress could be used for selecting tolerant genotypes under stress environments. These tolerant genotypes can be used to develop mapping populations to decipher the genes conferring tolerance as well as to study the molecular basis of tolerance.
由于全球气候变化，终端热胁迫已成为主要威胁之一，这对小麦作物的产量和生产力产生了重大影响。因此，有必要识别关键性状和基因型，以培育耐热小麦。本研究旨在比较热胁迫（HSE）和延长热胁迫（EHSE）对生殖阶段耐热和热敏感基因型的物候-生理-生化性状的影响。与HSE相比，EHSE下的物候性状显著降低。耐热基因型保持了物候-生理-生化性状的平衡，而热敏感基因型在两种胁迫条件下均表现出显著降低。在物候性状中，干物质（R = 0.52）和生育期（R = 0.44）对种子产量有积极影响，表明生物量和作物生育期对胁迫下的产量优势有贡献。在灌浆期，归一化植被指数（NDVI）和叶绿素（Chl）在HSE和EHSE条件下对籽粒产量均表现出持续的积极影响。这可能归因于终端热胁迫下衰老延迟和同化物转运改善导致的光合作用增强。HSE下，耐胁迫基因型中超氧化物歧化酶（SOD）、过氧化物酶（POX）和抗坏血酸过氧化物酶（APX）的生化活性被诱导。在HSE和EHSE条件下，冠层温度与物候-生理-生化性状的相关性保持不变，表明冠层温度是耐热性的最佳选择参数。与产量呈正相关且在胁迫下受影响较小的性状可用于在胁迫环境下选择耐胁迫基因型。这些耐胁迫基因型可用于构建作图群体，以破译赋予耐受性的基因，并研究耐受性的分子基础。
