Analysis of Genetic Diversity and Trapping Elite Alleles for Plant Height in Drought-Tolerant Wheat Cultivars

Plant height (PH) reduction has obviously contributed to lodging resistance and yield increase of wheat (Triticum aestivum L.) in the last decades. The objectives of this study were to understand the diversity status of wheat cultivars in northern China and to identify simple sequence repeat (SSR) markers associated with PH. Using 117 SSR markers evenly distributed on wheat chromosomes, a total of 1484 alleles were detected in 136 winter wheat cultivars that were historically planted in northern China. The average allele number per locus ranged from 2 to 42 with an average of 12.6. The polymorphism information content (PIC) values ranged from 0.016 to 0.941 with an average of 0.640. Based on the cluster tree, the cultivars developed by the same breeders or kin cultivars were gathered in the same subgroup. Some cultivars with similar ecotypes or developed contemporaneously also fell into the same subgroup. Nineteen SSRs each were significantly associated with PH under drought and well-watered conditions, respectively (P < 0.01), including 9 common markers, viz., Xbarc125 (7D), Xbarc168 (2D), Xgwm126 (5A), Xgwm130 (2B), Xgwm212 (5D), Xgwm285 (3B), Xgwm495 (4B), Xgwm95 (2A), and Xwmc396 (7B). The alleles of Xgwm285-220, Xgwm495-181, Xbarc125-167, and Xgwm212-99 were elite alleles for reducing PH.

摘要为了解北方冬麦区小麦抗旱品种的遗传多样性, 筛选株高相关标记的等位变异, 选用117个均匀分布于小麦各条染色体的SSR标记, 对136份小麦抗旱品种进行分析。共检测到1 484个等位变异, 平均每个标记12.6个等位变异, 变化范围为2$∼42个, 供试材料的多态性遗传信息含量(PIC)变化范围为0.016$∼0.941, 平均为0.640。聚类分析把同一地区或育种单位育成的品种、具有共同亲本的姊妹品种聚为一类, 部分相近年代选育的品种也分别聚在一类, 国外材料的基因导入对育成品种的遗传基础产生了影响。关联分析表明, 在旱地条件下与株高显著相关的标记有19个(P < 0.01), 其中6个极显著相关(P < 0.001); 在水地条件下与株高显著相关的标记也有19个, 其中7个极显著相关。水、旱两种条件下共检测出与株高极显著相关的标记9个, 分别是Xbarc125 (7D)、Xbarc168 (2D)、Xgwm126 (5A)、Xgwm130 (2B)、Xgwm212 (5D)、Xgwm285 (3B)、Xgwm495 (4B)、Xgwm95 (2A)和Xwmc396 (7B), 其中Xgwm285的220 bp、Xgwm495的181 bp、Xgwm212的99 bp和Xbarc125的167 bp等位变异是与矮秆关联的优异等位基因。