高粱棕色中脉基因bmr-6的遗传分析和SSR标记定位

Genetic analysis and mapping with SSR markers of the brown midrib gene bmr-6in Sorghum bicolor

高粱棕色突变体的叶片中脉是棕色的,此类突变体能使家畜难以消化的木质素含量降低40%～60%,从而大幅度提高了家畜对高粱秸秆的消化率。利用高粱棕色中脉材料N592(bmr-6类型)和白色中脉(Sa)进行杂交和自交,构建F2分离群体,F1表现为白色中脉,F2白棕分离比符合3∶1,说明棕色中脉基因受一对等位基因控制,表现为隐性遗传。用已知定位到连锁群上的微卫星标记对棕色中脉基因进行了连锁分析,发现1个与棕色中脉(bmr-6)基因连锁的微卫星标记,连锁距离为4.2cM,初步将该基因定位于第7连锁群。

The mutants,which produced brown leaf midribs,reduced the content of lignin by 40% to 60% compared with normal varieties.This low lignin content largely promoted the rate of digestion in livestock.The F2 population was constructed from the hybrid of N592（bmr-6）and Sa（white midrib）to map the bmr-6 gene. The ratio of white and brown midribs was 3to 1in the F2 population.Therefore,the bmr-6 gene is a single recessive gene.Using 171 SSR markers and F2recessive population,one SSR（simple sequence repeats）marker （txp295）that linked with the bmr-6gene was detected and the genetic distance was 4.2cM.In addition,the bmr-6gene was mapped to the seventh linkage group of sorghum because the txp295 marker was located on this linkage group.