不同水分环境下小麦株高性状QTL定位分析

QTL Mapping Analysis for Plant Height Traits in Wheat under Different Water Environments

为了发掘控制小麦抗旱节水相关性状的基因位点,为抗旱节水品种选育提供指导,本研究利用洛旱2号/潍麦8号的F8∶9群体的302份材料,在6个不同水分环境条件下进行试验,对小麦抗旱相关株高性状进行了QTL分析。结果显示,在所有环境中共检测到17个控制株高的加性QTL,主要分布在2B、3A、3B、4A、5A、5D、6B、7A和7B染色体上,加性效应值为1.9196-5.3828 cm,可解释3.3160%-26.9489%的表型变异。在充分灌溉条件下的E1、E2和E3三个环境中共有14个QTL位点,25次被检测到;在干旱胁迫环境下的E4、E5和E6三个环境中共有5个QTL位点,7次被检测到。在所有检测到的17个QTL位点中,有12个位点只在灌溉环境下被检测到,有3个位点只在干旱胁迫环境下被检测到,只有2个位点在灌溉和干旱胁迫环境下同时被检测到。表明基因的表达受环境条件的影响较大,在QTL水平上表明基因与环境之间存在互作。定位在7A染色体上位于Xbarc049和Xgwm273之间的q Ph-WL-7A.3,在三个水分胁迫环境下稳定表达,能增加株高2.4815-3.6972 cm,加性效应贡献率在8.6426%-10.0711%,是一个与水分高效利用密切相关的QTL,可用于小麦抗旱基因改良及分子标记辅助育种。

Plant height is one of the most important traits that associated with drought resistance of wheat. In order to explore the gene sites associated with drought resistance and water saving,and provide guidance for drought-resistant breeding of wheat,the plant height QTL was evaluated with the population of302 recombinant inbred lines derived from a cross between drought-tolerant cultivar Luohan 2 and water-sensitive cultivar Weimai 8 in 6 different water regimes. Total 17 additive QTL loci for plant height were identified,and they distributed on chromosomes 2B,3A,3B,4A,5A,5D,6B,7A and 7B,respectively. These QTL loci could explain the phenotypic variations varied from 3. 3160% - 26. 9489% with the additive effects of 1. 9196 - 5. 3828 cm. Of which,14 QTL loci were detected for 25 times in 3 irrigation environments（ E1,E2 and E3）,and 5 QTL loci were detected for 7 times in 3 drought stress environments（ E4,E5 and E6）. Of all the 17 QTL loci for plant height,12 QTL loci were detected only in irrigation environment,3 QTL loci were detected only in drought stress environment,and 2 QTL loci were detected in both environments. It suggested that the expression of these genes were greatly influenced by environmental condition,and showed that therewas interaction between gene expression and environment on the level of QTL. q Ph-WL-7A. 3,which was located between Xbarc049 and Xgwm273 on 7A,could stably express in all the three drought stress environments,and increase plant height for 2. 4815 - 3. 6972 cm with the contributions of additive effects as8. 6426% - 10. 0711%. It indicated that the QTL was closely related to water efficient utilization and could be used in the genetic improvement of drought tolerance and molecular marker assisted breeding of wheat.