冷水胁迫下水稻幼苗期根系性状的QTL分析

本研究以籼粳交“密阳23/吉冷1号”的F_2∶3 代200个家系作为作图群体，在自然和12℃冷水胁迫下，进行水稻幼苗期根系性状的鉴定，并以利用SSR标记构建的分子连锁图谱为基础，对水稻幼苗期的根数、最大的根长、最大根的根径、根干重、根/苗比等根系性状进行了数量性状位点（QTLs）分析。结果表明，上述根系性状在F₃代家系群均表现为连续分布，认为是由多基因所控制的数量性状。冷水胁迫下，在第1、2、6、11和12染色体上共检测到与根系性状相关的QTL 17个，对表型变异的解释率为5.8%～15.2%，其中与最大根的根径相关，位于第2染色体RM263-RM6区间的qCRD2和位于第11染色体RM21-RM206区间的qCRD11，以及与根干重相关，位于第2染色体RM262-RM263区间的qCRWT2和位于第11染色体RM229-RM21区间的qCRWT11贡献率较大，分别为15.0%、15.2%、10.6%和12.2%。这些基因的作用方式为部分显性或显性或超显性。

QTL Analysis of Root Traits at the Seedling Stage in Rice under Cold Water Irrigation

The quantitative trait loci (QTLs) for root traits, such as root number, the longest root length, the diameter of longest root, root dry weight, ratio of root to seedling at the seedling stage in rice under 12℃ cold water irrigation and natural condition was identified by using F_2∶3 population including 200 individuals and lines derived from a cross of indica and japonica “Milyang23/Jileng1” with microsatellite markers. All of root traits at the seedling stage showed a continuous distribution in F₃ lines, which were quantitative traits controlled by many genes. Seventeen QTLs on chromosome 1, 2, 6, 11 and 12, which associated with root traits at the seedling stage under cold water irrigation were detected, which explained the range of the observed phenotypic variance from 5.8% to 15.2%. Among them, qCDR2 and qCDR11 located on RM263-RM6 of chromosome 2 and RM21-RM206 of chromosome 11, respectively, which associated with the diameter of longest root could account for 15.0% and 15.2% of observed phenotypic variation, respectively. qCRWT2 and qCRWT11 located on RM262-RM263 of chromosome 2 and RM229-RM21 of chromosome 11, respectively, which associated with root dry weight could account for 10.6% and 12.2% of observed phenotypic variation, respectively. These gene action was partional dominance or dominance or over dominance.