高丹草氢氰酸含量性状的QTL定位分析

为了深入开展高丹草低氢氰酸含量性状的QTL精细定位、基因图位克隆、功能解析及分子标记辅助育种,该研究以二倍体杂交高丹草F_2代群体500个分离单株无性系及其亲本为材料,在课题组前期已构建出的高丹草高密度分子遗传连锁图谱的基础上,利用区间作图法对两年两地测定的高丹草氢氰酸含量性状进行了QTL定位分析。结果显示:(1)在4个不同环境下高丹草氢氰酸含量性状的广义遗传率分别为61.70%、72.05%、40.16%和69.25%,表明氢氰酸含量是既受环境影响又受微效多基因控制的数量性状,而且其群体测定值频率呈明显单峰正态性分布特点,符合QTL定位要求。(2)在LOD2.5的条件下,共检测到16个与氢氰酸含量性状相关的QTLs,其分布在LG1、LG2、LG4、LG6、LG7、LG8和LG10连锁群上。(3)16个QTLs中能重复检测到的稳定QTLs有9个,遗传贡献率范围为1.17%～39.9%,其中贡献率大于20%的主效QTLs有Qcn2-2、Qcn4-1、Qcn6和Qcn6-1共4个。该研究结果明确了各QTLs的遗传效应和分子标记位点。

QTL Mapping of Hydrocyanic Acid Content in Sorghum Sudangrass

In order to intensify QTL fine mapping, map based gene cloning, functional analysis and molecular marker assisted breeding of the low hydrocyanic acid content trait of sorghum sudangrass, we used 500 isolated individual clone plants and their parents of diploid hybrid sorghum sudangrass F₂ generation population as materials, which was constructed in the early stage of the research group. The QTL mapping of hydrocyanic acid content trait of the high density molecular linkage map of sorghum sudangrass was determined by interval mapping method. The results showed that: (1) the generalized heritability of the hydrocyanic acid traits in the four different environments was 61.70%, 72.05%, 40.16% and 69.25%, respectively, indicating that the hydrocyanic acid content is both environmentally affected and controlled by micro effects. The frequency of population measurements showed a characteristic of single peak normal distribution, which met the QTL mapping requirements. (2) Under the condition of LOD>2.5, 16 QTLs related to hydrocyanic acid traits were detected, which were distributed on LG1, LG2, LG4, LG6, LG7, LG8 and LG10 linkage groups. (3) There are 9 stable QTLs that can be repeatedly detected in 16 QTLs, and the genetic contribution rate ranges from 1.17% to 39.9%. Among them, the main QTLs with contribution rate >20% are Qcn2 2, Qcn4 1, Qcn6 and Qcn6 1, a total of four. The experiment identified the genetic effects and molecular marker sites of each QTL.