Pandey Ankita, Harohalli Masthigowda Mamrutha, Kumar Rakesh, Pandey Girish Chandra, Awaji Sushma M, Singh Gyanendra, Pratap Singh Gyanendra
ICAR-Indian Institute of Wheat and Barley Research, Karnal, Haryana 132001 India.
Biosciences and Biotechnology, Banasthali Vidyapith, Banasthali, Rajasthan 304022 India.
Physiol Mol Biol Plants. 2023 Jan;29(1):131-143. doi: 10.1007/s12298-022-01267-4. Epub 2022 Dec 26.
Thermal stress is a major abiotic stress in wheat and is highly complex in mechanism. A large area in northwestern plain zones (NWPZ), which is the wheat bowl of India is affected by heat stress. Climate change also causes an abrupt increase in temperature at different growth stages of wheat. Thus, wiser selection of stress tolerant varieties is an important strategy to combat the climate change effect. The present study aims for physiological and biochemical screening of timely sown NWPZ wheat varieties (WB2, HD3086, DBW88, DPW621-50, DBW17, HD2967 and PBW550) of India for their thermal stress tolerance along with heat tolerant (RAJ3765) and susceptible checks (RAJ4014) at seedling stage. The experiment was conducted in completely randomized design under controlled laboratory condition and heat stress was induced at 37 °C at seedling stage. Later different physio-biochemical traits were studied in both control and stress seedlings. All traits exhibited significant variations among genotypes under heat stress condition. Root and shoot weight, relative water content, chlorophyll content index and chlorophyll fluorescence reduced significantly, whereas membrane leakage, osmotic potential, catalase, ascorbate peroxidase, guaiacol peroxidase, malondialdehyde content and proline content were increased in stress plants. A tolerance matrix was prepared based on stress response of the genotypes for each trait and a final tolerance score was given to each genotype. Based on this tolerance matrix, DBW88 and PBW550 were identified as tolerant, DPW621-50, DBW17 and HD2967 as moderately susceptible and HD3086 and WB2 as susceptible to heat stress. Earlier studies parade that seedling level stress tolerance has high correlation with adult level stress tolerance under field condition in wheat. Hence, this study helps in wiser selection of varieties for sowing in NWPZ based on weather forecast of the location for creating varietal mosaic in context of climate change.
热胁迫是小麦面临的主要非生物胁迫，其机制高度复杂。印度的“小麦之乡”西北平原地区的大片区域受到热胁迫影响。气候变化还导致小麦不同生长阶段的温度突然升高。因此，明智地选择耐胁迫品种是应对气候变化影响的重要策略。本研究旨在对印度西北平原地区适时播种的小麦品种（WB2、HD3086、DBW88、DPW621 - 50、DBW17、HD2967和PBW550）进行生理生化筛选，以确定其在苗期的热胁迫耐受性，同时设置耐热品种（RAJ3765）和敏感对照品种（RAJ4014）。该实验在可控的实验室条件下采用完全随机设计进行，在苗期将温度升至37°C诱导热胁迫。随后对对照和胁迫处理的幼苗进行了不同生理生化性状的研究。在热胁迫条件下，所有性状在基因型间均表现出显著差异。胁迫处理的植株中，根和地上部重量、相对含水量、叶绿素含量指数和叶绿素荧光显著降低，而膜透性、渗透势、过氧化氢酶、抗坏血酸过氧化物酶、愈创木酚过氧化物酶、丙二醛含量和脯氨酸含量增加。根据各基因型对每个性状的胁迫响应制备了耐受性矩阵，并为每个基因型给出了最终的耐受性评分。基于该耐受性矩阵，DBW88和PBW550被鉴定为耐胁迫品种，DPW621 - 50、DBW17和HD2967为中度敏感品种，HD3086和WB2为热敏感品种。早期研究表明，小麦在田间条件下苗期的胁迫耐受性与成株期的胁迫耐受性高度相关。因此，本研究有助于根据该地区的天气预报，在气候变化背景下明智地选择适合在西北平原地区播种的品种，以构建品种多样性。
