稻米胚重相关性状QTL分析

QTL Analysis of Embryo Weight Correlative Traits in Rice (Oryza sativa L.)

利用米粒胚重差异显著的广东早籼品种窄叶青 8号 (ZYQ8)和北方粳稻品种京系 17(JX17) ,以及由它们构建的加倍单倍体 (DH)群体 12 7个株系 ,对糙米重、胚乳重、胚重和胚重率 4个性状进行了评价与QTL分析。 4个性状表现型均为连续分布 ,且都存在一定数量的双向超亲遗传类型 ,受多基因控制。共检测到 13个影响 4个性状的QTL ,分布于第 2、3、4、6、9、10和 12染色体上 ,其中糙米重 4个、胚乳重 5个、胚重 2个和胚重率 2个。控制糙米重的 4个QTL与控制胚乳重的QTL位于相同的区间 ,说明糙米重与胚乳重之间存在着密切的遗传关系。胚重qEW 3和qEW 4的LOD值分别为2 89和 3 34,对表型变异的贡献率为 13 8%和 14 1%。qEW 3上来自JX17的等位基因使胚重增加 ,而qEW 4的增效等位基因来自ZYQ 8。在第 4、9染色体上 ,各检测到胚重率的QTL ,其LOD值分别为 2 92和 2 6 3,贡献率为 10 6 %和11 2 % ,它们的增效等位基因均来自ZYQ 8。分析表明 ,这些QTL与控制巨大胚ge基因不在同一条染色体上。

QTLs for 4 embryo weight correlative traits including brown rice weight (BRW), endosperm weight (ENW), embryo weight (EW) and embryo weight rate (EWR), were investigated by using a population of 127 DH lines derived from a cross between JX17 and ZYQ8. Transgressive segregations for the 4 traits were observed in the population, and their distributions were approximately normal. A total of 13 QTLs affecting these traits were detected on chromosome 2, 3, 4, 6, 9, 10 and 12 including four QTLs for BRW, five QTLs for ENW, two QTLs for EW and two QTLs for EWR. Four QTLs for BRW were located on the same regions with those for ENW, which showed there is close genetic correlation between BRW and ENW. Two QTLs (qEW-3 and qEW-4)for EW were detected on chromosome 3 and 4. LOD values of the two QTLs were 2.89 and 3.34, and their contributions were 13.8% and 14.1%, respectively. The allele of qEW-3 from JX17 would increase EW, while the allele of qEW-4 from ZYQ8 would increase EW. Two QTLs controlling EWR were detected on chromosome 4 and 9 (qEWR-4 and qEWR-9). Their LOD values were 2.92 and 2.63, and the explained phenotypic variation was 10.6% and 11.2%, respectively. Both of the alleles from ZYQ8 increased EWR. It was indicated that the QTLs controlling embryo correlative traits in this population were affected by minor genes located on different chromosomes from that of giant embryo gene (ge).