Fu Jianming, Bowden Robert L, Jagadish S V Krishna, Prasad P V Vara
Department of Agronomy, 2004 Throckmorton Plant Sciences Center, Kansas State University, Manhattan, KS, United States.
USDA-ARS Hard Winter Wheat Genetics Research Unit, 4008 Throckmorton Plant Sciences Center, Kansas State University, Manhattan, KS, United States.
Front Plant Sci. 2023 Feb 22;14:1132108. doi: 10.3389/fpls.2023.1132108. eCollection 2023.
In many regions worldwide wheat ( L.) plants experience terminal high temperature stress during the grain filling stage, which is a leading cause for single seed weight decrease and consequently for grain yield reduction. An approach to mitigate high temperature damage is to develop tolerant cultivars using the conventional breeding approach which involves identifying tolerant lines and then incorporating the tolerant traits in commercial varieties. In this study, we evaluated the terminal heat stress tolerance of 304 diverse elite winter wheat lines from wheat breeding programs in the US, Australia, and Serbia in controlled environmental conditions. Chlorophyll content and yield traits were measured and calculated as the percentage of non-stress control. The results showed that there was significant genetic variation for chlorophyll retention and seed weight under heat stress conditions. The positive correlation between the percent of chlorophyll content and the percent of single seed weight was significant. Two possible mechanisms of heat tolerance during grain filling were proposed. One represented by wheat line OK05723W might be mainly through the current photosynthesis since the high percentage of single seed weight was accompanied with high percentages of chlorophyll content and high shoot dry weight, and the other represented by wheat Line TX04M410164 might be mainly through the relocation of reserves since the high percentage of single seed weight was accompanied with low percentages of chlorophyll content and low shoot dry weight under heat stress. The tolerant genotypes identified in this study should be useful for breeding programs after further validation.
在世界许多地区，小麦（L.）植株在灌浆期会遭受高温胁迫，这是导致单粒重下降进而造成粮食减产的主要原因。减轻高温损害的一种方法是采用传统育种方法培育耐逆品种，该方法包括鉴定耐逆品系，然后将耐逆性状整合到商业品种中。在本研究中，我们在可控环境条件下评估了来自美国、澳大利亚和塞尔维亚小麦育种项目的304个不同的优良冬小麦品系对后期热胁迫的耐受性。测量了叶绿素含量和产量性状，并计算其相对于非胁迫对照的百分比。结果表明，在热胁迫条件下，叶绿素保留率和种子重量存在显著的遗传变异。叶绿素含量百分比与单粒重百分比之间存在显著的正相关。提出了灌浆期耐热性的两种可能机制。一种以小麦品系OK05723W为代表，可能主要通过当前的光合作用，因为单粒重的高百分比伴随着叶绿素含量的高百分比和地上部干重的增加；另一种以小麦品系TX04M410164为代表，可能主要通过储备物质的重新分配，因为在热胁迫下，单粒重的高百分比伴随着叶绿素含量的低百分比和地上部干重的降低。本研究中鉴定出的耐逆基因型经过进一步验证后，应可用于育种项目。
