碱胁迫下粳稻幼苗前期耐碱性的数量性状基因座检测

以粳粳交“高产106/长白9号”F_2:3代200个家系为作图群体, 在0.15% Na₂CO₃溶液的碱性胁迫下, 进行了水稻耐碱性鉴定, 并以SSR标记构建的分子连锁图谱为基础, 对水稻幼苗前期的根数、根长和苗高及其相对碱害率进行了数量性状基因座(QTLs)的检测。结果表明, 上述性状在F₃家系群中均表现为具有1~2个峰的连续分布, 认为由主效基因和微效基因共同控制的数量性状。共检测到与碱胁迫下幼苗前期根数、根长和苗高及其相对碱害率相关的QTL 26个, 分布于第1、5、6、7、8、9和11染色体上。其中, 碱胁迫下与根数相关的QTL 4个, qRN6-1和qRN11对表型变异的解释率较大, 分别为29.91%和13.42%；与根数相对碱害率相关的QTL 5个, qRRN11-2对表型变异的解释率较大, 为23.86%；与根长相关的QTL 6个, qRRL11-2对表型变异的解释率较大, 为21.06%；与根长相对碱害率相关的QTL 2个, 但对表型变异的解释率均较低；与苗高相关的QTL 5个, qSH1和qSH11-2对表型变异的解释率较大, 分别为15.81%和16.53%；与苗高相对碱害率相关的QTL 4个, qRSH5和qRSH6-2对表型变异的解释率分别为29.89%和34.63%。而这些解释率较大的QTL所处的标记区间距离, 除qRN6-1相对较小(19.0 cM)外, 其余QTL的标记区间距离均大于26.3 cM, 需作进一步的精细定位。在所检测到的QTL中, 13个QTL的增效等位基因均来自耐碱亲本长白9号, 而其余QTL的增效等位基因来自敏碱亲本高产106；基因的主要作用方式为超显性或部分显性。

Identification of Quantitative Trait Loci for Alkaline Tolerance at Early Seed-ling Stage under Alkaline Stress in Japonica Rice

The quantitative trait loci (QTLs) for root number, root length, seedling height and their relative alkaline damage rates at early seedling stage in rice under 0.15% Na₂CO₃ alkaline stress were identified using a F_2:3 population, which included 200 individuals and lines derived from a cross between two japonica rice cultivars Gaochan 106 and Changbai 9 with microsatellite markers. All the traits above showed a continuous distribution with 1 or 2 peaks in F₃ lines under alkaline stress, which were the quantitative traits controlled by major and multiple QTLs. Twenty-six QTLs associated with root number, root length and seedling height and their relative alkaline damage rates at early seedling stage under alkaline stress were detected, and which were located on chromosomes 1, 5, 6, 7, 8, 9, and 11. These QTLs included 4 QTLs associated with root number, 5 QTLs correlated with relative alkaline damage rate for root number, 6 QTLs controlling root length, 2 QTLs for relative alkaline damage rate for root length, 5 QTLs associated with seedling height, 4 QTLs related to relative alkaline damage rate for seedling height. qRN6-1, qRN11, qRRN11-2, qRRL11-2, qSH1, qSH11-2, qRSH5, and qRSH6-2, accouonted for 29.91, 13.42, 23.86, 21.06, 15.81, 16.53, 29.89, and 34.63% of the observed phenotypic variation, respectively. While the marker flanking distance of these QTLs explained larger. The observed phenotypic variation were more than 26.3 cM, except qRN6-1 with 19.0 cM of marker flanking distance, which should be conducted more refined mapping further. Of detected QTLs, the alleles for 13 QTLs originated from the tolerant parent Changbai 9, and the alleles of other QTLs were derived from alkaline sensitive parent Gaochan 106. These gene actions showed mainly part dominance or over dominant effects.