小麦株高QTL定位及其水分环境互作遗传分析

QTL Mapping and QTL × Environmental Interactions for Plant Height in Wheat

为探讨小麦株高（PH）分子数量性状遗传及其QTL与水分环境互作关系,以冬小麦重组近交系群体（RIL）（陇鉴19（耐旱）×Q9086（水分敏感））120个株系为试验材料,采用条件复合区间作图法对4个环境不同水分条件下株高进行QTL定位分析。结果表明,小麦RIL群体株高对水分环境反应敏感,群体中各株系呈现广泛变异和超亲分离,属于微效多基因控制的复杂数量性状,易受水分环境影响。共检测到19个和45对控制株高的加性QTL（AQTL）和上位性QTL（AA-QTL）,分布在除3D以外的其他20条染色体上。这些A-QTL和AA-QTL表达通过正向或负向调控影响株高表型变异,贡献率分别为0.47%-7.14%和0.34%-2.93%。发现了2个多环境均能稳定表达的AQTL（Qph.acs-5A.1和Qph.acs-7A.1）,以及2个A-QTL热点区域（Xbarc1072-XBarc167（2B）和Xksum253-Xbarc164（5B））。所检测到的A-QTL和AA-QTL与干旱胁迫环境互作普遍负向调控株高表型。加性效应和上位性效应是决定小麦株高的主要遗传因子。在干旱胁迫条件下,这种遗传主效应均不同程度降低株高表型。可为小麦抗旱遗传改良和分子标记辅助选择育种奠定理论基础。

Known better the molecular quantitative genetic and QTL interactions with water environments of plant height（ PH） in wheat,QTL mapping was performed for PH by a mixed linear model approach. The PH was evaluated by the population of 120 recombinant inbred lines derived from a cross between drought-tolerant cultivar Longjian 19 and water-sensitive cultivar Q9086 under different water regimes in four environments. Phenotypes of PH from RILs were significantly sensitive to water conditions and showed wide variations and transgressive segregations. The inheritance of PH was substantially modulated by minor-effect polygenes and their interactions with water environments. 19 additive QTLs（ A-QTLs） and 45 epistatic QTLs（ AA-QTLs） for PH were identified and widely distributed on all chromosomes besides 3D. The expression of these QTLs might influence the phenotypic variation of PH by the up-and down-regulation,accounted for variations of PH by 0. 47%-7. 14% and 0. 34%-2. 93%,respectively. Two A-QTLs,Qph.acs-5A.1 and Qph.acs-7A.1,could be detected in multi-environments. In addition,two A-QTL hot-spot regions for PH were also found in some specific intervals,e. g.,Xbarc1072-XBarc167 on chromosome 2B and Xksum253-Xbarc164 on chromosome 5B. Most of interaction effects of A-QTLs and AA-QTLs with drought-stressed environments showed the down-regulation for the PH variations. The additive and the epistatic effect could be main genetic factors controlled the PH inheritance,which expressions might decrease PH. The infor-mation in this study should be useful for the genetic improvement of drought tolerance and molecular marker-assisted selection in wheat.