小麦萌发期幼苗相关性状耐旱系数的QTL定位

QTL Mapping for Drought-tolerance Coefficient of Seedling Related Traits During Wheat Germination

为了检测与小麦幼苗耐旱性相关的数量性状位点,用3个关联重组自交系(RIL)群体,对小麦萌发期幼苗的胚芽鞘长、苗高、最大根长、根数、苗鲜重、茎叶鲜重、根鲜重、根冠鲜重比、苗干重、茎叶干重、根干重、根冠干重比等12个表型性状的耐旱系数进行QTL定位。结果显示,共检测到28个耐旱相关位点,分布在小麦的1BL、1D、2B、3A、3B、3D、4A、6A、6B、6D、7A、7B等12条染色体上,可分别解释表型变异的5.61%~64.22%,其中,6个位点通过同一群体不同性状的耐旱系数检测到,2个位点通过2个群体不同性状的耐旱系数检测到,分别位于4A染色体的Xbarc61~wpt-9675标记区间和6A染色体的wpt-9679~wpt-8177标记区间内,这2个位点实现了在不同群体间的相互验证,可靠性大大提高。这些位点的发现对于小麦萌发期耐旱性的精细定位、图位克隆和分子标记辅助选择具有重要的意义。

For discovering the quantitative trait loci （QTLs） contributing to drought tolerance of seedling during germination, QTL analyses for drought-tolerance coefficients of 12 seedling traits： coleoptile length, seedling height, longest root length, root number, seedling fresh weight, stem and leaves fresh weight, root fresh weight, root-to-shoot fresh weight ratio, seedling dry weight, stem and leaves dry weight, root dry weight, and root-to-shoot dry weight ratio, were conducted using three F9 recombinant inbred lines （RIL） populations. Total 28 QTLs related to drought tolerance were mapped on 12 chromosomes 1BL, 1D, 2B, 3A, 3B, 3D, 4A, 6A, 6B, 6D, 7A, and 7B, accounting for 5.61% -64.22% of phenotypic variance. Among these QTLs, six were detected by drought-tolerance coefficients of different seedling traits in a same population, and two loci located on chromosome 4A in interval Xbare61- wpt -9675 and 6A in interval wpt-9679 -wpt- 8177 were detected in two different populations, which were more reliable for realizing the mutual authentication between different populations. Our work has an important significance for fine mapping technique, map-based cloning, and marker-assisted selection of drought tolerance in wheat.