Climate change is adversely affecting wheat yields as the associated rising temperatures damage its reproductive physiology. Heat stress affects wheat at various stages of growth, but flowering and reproductive phases are the most sensitive to high temperatures as flower opening usually occurs in cooler environments. Heat stress at meiosis causes ovule and pollen sterility along with anther dehiscence. During pollen development, temperatures >30°C cause pollen abortion. At anthesis, heat stress limits resource translocation to developing grain, resulting in small grain and low yields. During grain development, heat stress shortens the grain-filling duration and decreases starch and protein accumulation due to reduced activity of grain biosynthesis enzymes and impaired flag leaf assimilatory efficiency and stem reserve mobilization. The development of heat-tolerant wheat genotypes through screening, selection and breeding using genetic engineering, exogenous application of osmoprotectants and agronomic approaches is a high priority. This review discusses the impact of heat stress on flower development and fertilization, grain development and reproductive failure in wheat and outlines strategies (i.e. breeding and selection, genetic engineering, molecular breeding and management) to improve heat tolerance in wheat.

中文翻译：

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热应激对小麦生殖生理和产量的影响

气候变化正在对小麦产量产生不利影响，因为相关的温度升高会损害其生殖生理。热应激影响小麦在不同生长阶段，但开花和生殖阶段对高温最敏感，因为开花通常发生在较冷的环境中。减数分裂时的热应激导致胚珠和花粉不育以及花药开裂。在花粉发育过程中，温度>30°C 会导致花粉流产。在开花期，热应力限制了资源向发育中的籽粒转移，导致籽粒小，产量低。在籽粒发育过程中，热应激由于降低籽粒生物合成酶的活性和损害旗叶同化效率和茎干储备动员，缩短了籽粒灌浆期，减少了淀粉和蛋白质的积累。通过基因工程筛选、选择和育种、渗透保护剂的外源应用和农艺方法开发耐热小麦基因型是当务之急。这篇综述讨论了热应激对小麦花发育和受精、籽粒发育和繁殖失败的影响，并概述了提高小麦耐热性的策略（即育种和选择、基因工程、分子育种和管理）。