Prasad P V Vara, Djanaguiraman Maduraimuthu
Department of Agronomy, 2004 Throckmorton Plant Science Center, Kansas State University, Manhattan, KS 66506, USA.
Funct Plant Biol. 2014 Dec;41(12):1261-1269. doi: 10.1071/FP14061.
Short episodes of high temperature (HT) stress during reproductive stages of crop development cause significant yield losses in wheat (Triticum aestivum L.). Wheat plants of cultivar Chinese Spring were grown at various temperature regimes at several stages of reproductive development for different durations. The objectives of this research were to (i) identify the stage(s) most sensitive to HT stress during reproductive development, and (ii) determine threshold temperature and duration of HT stress that decrease floret fertility and individual grain weight. Two periods (first at 8-6 days before anthesis and second at 2-0 days before anthesis) during reproductive development were most sensitive to short episodes (2 or 5 days) of HT stress, causing maximum decreases in floret fertility. Short episodes (5 days) of mean daily temperatures >24°C imposed at start of heading quadratically decreased floret fertility, with the values reaching close to 0% around mean daily temperature of 35°C; and floret fertility and individual grain weight decreased linearly with increasing duration (in the range from 2 to 30 days) of HT stress when imposed at start of heading or start of grain filling respectively. HT stress caused morphological abnormalities in pollen, stigma and style. The combination of lower floret fertility (leading to decreased grain numbers) and decreased individual grain weights can cause significant decreases in grain yield. Further research to search for genetic variability for these traits and use them in breeding programs to develop tolerant genotypes that can provide yield stability under current and future climates is warranted.
在作物发育的生殖阶段，短期高温胁迫会导致小麦（Triticum aestivum L.）显著减产。中国春小麦品种的植株在生殖发育的几个阶段，于不同温度条件下生长不同时长。本研究的目的是：（i）确定生殖发育过程中对高温胁迫最敏感的阶段；（ii）确定降低小花育性和单粒重的高温胁迫阈值温度和持续时间。生殖发育过程中的两个时期（第一个时期在开花前8 - 6天，第二个时期在开花前2 - 0天）对短期（2或5天）高温胁迫最为敏感，导致小花育性最大程度降低。抽穗初期施加平均日温>24°C的短期（5天）高温胁迫，小花育性呈二次方下降，在平均日温约35°C时，小花育性值接近0%；分别在抽穗初期或灌浆初期施加高温胁迫时，小花育性和单粒重随高温胁迫持续时间（2至30天）增加呈线性下降。高温胁迫导致花粉、柱头和花柱出现形态异常。小花育性降低（导致粒数减少）和单粒重下降共同作用，会使籽粒产量显著降低。有必要进一步开展研究，寻找这些性状的遗传变异，并将其应用于育种计划，以培育出在当前和未来气候条件下能够实现产量稳定的耐逆基因型。
