Improving Sclerotinia Sclerotiorum Resistance Of Ogu CMS Restorer Lines By Molecular Marker-assisted Selection In Brassica Napus

Rapeseed (Brassica napus) is one of the most important oil crops in the world. In recent years, with the increase of domestic consumption of vegetable oil, the oil supply has been seriously insufficient. Sclerotinia sclerotiorum is one of the most serious diseases in rapeseed, which causes severe yield losses in rapeseed production.In previous study, a wild B. incana, COl with high level of resistance were identified with resistant loci, resynthesize B. napus AC 1-4 was resynthesized by crossing C01 with B. rapa (6Y733).Here the 4Q292 with high level of resistance to sclerotinia were developed from the progenies between Ogu CMS hybrid,4Q292 and AC 1-4 with molecular marker assisted selection. The results are shown as follows.There were 69 fertile and 77 sterile individuals of Yx derived from cross between 4Q292 and AC1-4. The segregation ratio of fertility:sterility agreed with 1:1. It showed that the fertility restore of Ogu CMS is regulated by a dominant gene. The fertile individuals of F1 were screened for resistance via screening resistant loci with 9 SSR markers linked with resistant QTL and evaluating resistance of the detached stem. Two individuals (4C99 and 4C115) with good fertility and resistance in Fl, were selected to develop F2 populations, which were screened for resistant loci with SSR markers and seed quality with NIRS. Among 59 and 65 fertile individuals of F2, 8 excellent plants were chosen with resistant loci and improved seed quality to develop 980 F3 individuals, which were screened for resistance loci with molecular marker. A total of 50 plants with resistant loci had higher resistance than 25 plants without resistant loci and Zhongshuang 9 as control. Via analysis of seed quality, two lines,5X80-7 and 5X82-7 with low erucic acid and 5X82-2 with low glucosinolate content were chosen for further breeding.