RAPD markers linked to microspore embryogenic ability in Brassica crops

In order to identify the markers linked to microspore embryogenic ability in Brassica crops, RAPD segregation analyses were performed in a microspore-derived (MD) population and a F-2 population derived from F-1 between 'Ho Mei' (high responsive parent in microspore embryogenesis) and '269' (low responsive parent) in Chinese cabbage, and between 'Lisandra' (high responsive parent) and 'Kamikita' (low responsive parent) in oilseed rape. After 230 and 143 primers were screened, a total of 148 and 52 markers were detected to be polymorphic between the parents in Chinese cabbage and oilseed rape, respectively. Twenty-seven percent of the markers in the MD population showed a significant segregation distortion in both crops. Of the markers showing segregation distortion in the MD population, 71-75% of the markers followed the expected Mendelian segregation ratio in the F-2 population. When the relationships between such distorted markers and microspore embryogenesis of the F-2 population were examined, 7 and 3 markers were identified to be associated with embryogenic ability in Chinese cabbage and oilseed rape, respectively. These markers showed additive effects on embryo yields, and the plants having more alleles of the high responsive parent produced higher embryo yields. These markers may be useful in marker-assisted selection for improving microspore responsiveness traits in Brassica crops.