Development, inheritance and breeding potential of a recessive genic male sterile line D248A in Sesame (Sesamum indicum L.)

Genic male sterility (GMS) has great potential for heterosis exploitation in sesame (Sesamum indicum L.). Two spontaneous male-sterile plants were discovered in a Chinese sesame cultivar (Zhuzhi 4) in 2006. By consecutive sib mating with fertile plants from Zhuzhi 4, a new sterile line, D248A, was developed. Anatomy studies showed that D248A has thin, small and greenish anthers on which there are no or little pollen grains. The pollens are irregularly shaped and completely aborted, resulting in no germination and no formation of pollen tubes as revealed by acetocarmine stain or semi-solid suspension culture. Furthermore, D248A has a better performance in growth vigor, bloom duration and yield per plant than the other GMS lines (i.e. 95 ms-2A and 95 ms-5A). To investigate the inheritance mode of fertility, D248A was crossed and backcrossed with six varieties, and a segregating ratio of 3:1 and 1:1 for fertile and sterile plants was observed in F(2) and BC(1) populations, respectively. These results suggested that D248A is controlled by a recessive GMS gene. The average yield of four D248A-derived F(1) hybrids is as high as 1695 kg·ha(-1), which is almost twice of that of 95 ms-5A-derived F(1) hybrids. These results indicated that this newly developed recessive GMS line has great potential in sesame hybrid breeding.