Investigation Of Rapeseed Intersubgenomic Heterosis And Primary Dissection Of Genetic Basis

Rapeseed is an important oil crop in China,the planting area is the sixth in the crops. The status of rapeseed can be seen.Brassica napus is the main cultivar type.Although the methods of utilizing the heterosis of Brassica napus are various,the potential exploitation of heterosis has come to bottleneck.How to increase the yield of Brassica napus hybrids further is a problem that the breeders are facing.Our lab have being attempted to utilize the Brassica carinata and Brassica rapa which are rich in china.The heterosis potentiality of Brassica napus can be enhanced by utilizing subgenomic heterosis.The materials of the study are new-typed Brassica napus that contain various content of Brassica carinata and Brassica rapa genomes.We make cross between natural Brassica napus gene male sterile lines and our new-typed Brassica napus.The results of study show:1.The hybrids have great heterosis at the traits of seed yield in two years.In 2005-2006,the seed yield of twenty-five percent of combinations exceed the Huaza 6.In 2007-2008,the seed yield of forty percent of combinations exceed the Huaza 6.2.The traits of seed weight and pod number of yield component factors have also great heterosis in two years.In 2005-2006,the seed weight of fifty-seven percent of combinations exceed the Huaza 6,the pod number of seventy-six percent of combinations exceed the Huaza 6.In 2006-2007,the seed weight of twenty-nine percent of combinations exceed the Huaza 6,the pod number of twenty-eight percent of combinations exceed the Huaza 6.3.Other agronomic traits have great heterosis in two years.In 2005-2006,the plant height of thirty-eight percent of combinations exceed the Huaza 6.In 2006-2007,the plant height of fourteen percent of combinations exceed the Huaza 6.Above results,suggested that utilizing the subgenomic heterosis to improve the heterosis of Brassica napus is feasible.To dissection the genetics basis of heterosis of subgenomic can be used as theoretical guidance for utilizing the heterosis of subgenomic.We use a lot of SSR markers to dissect the polymorphism of genotype of new-typed Brassica napus and natural Brassica napus gene sterile male lines.Through analyzing the genetic distance between new-typed Brassica napus and natural Brassica napus gene sterile male lines.We find that it is significant positive correlation between heterosis and genetic distance.So the genetic distance between new-typed Brassica napus and natural Brassica napus gene sterile male lines is the greater and the better.In order to know more clear about the genetic basis of subgenomic heterosis,We use 529 markers to detect the loci which are linked to heterosis loci.Utilizing the phenotype data of seed yield for two years and the genotype data of DNA markers,We scan the loci at the genetic map.A lot of loci have obtained in the successive two years.There are three markers which are obtained in the successive two years.These markers are Na10C01-4, Na14G02-3 and niab071d.