Rapid Creation of Interspecific Hybrid Progeny to Broaden Genetic Distance through Double Haploid (DH) Inducer in Brassica napus

Interspecific hybridization of rapeseed is an important way to innovate breeding resources. This research used Brassica napus and Brassica rapa for artificial synthesis interspecific hybridization of F(1). The F(1) self-fruiting rate was particularly low. By comparing the fertilization rate and seed setting rate of nine crosses and selfing combinations of interspecific hybrid progeny F(1) and control B. napus, the results proved that the genetic stability of egg cells was greater than that of sperm cells, so the F(1) could get seed by artificial pollination with other normal pollen. Based on these results, interspecific maternal inbred offspring (induced F(1)) from egg cells was obtained by emasculation and pollination with the pollen of DH inducer Y3380. It was found through morphological analysis, flow cytometry identification, and meiotic observation of induced F(1), the plants had most normal fertile tetraploid and the meiosis was normal. The FISH results showed that the induced F(1) were B. napus (2n = 4x = 38, AACC), 20 A and 19 C chromosomes. The results of SNP chip detection and genetic cluster analysis found that the genetic variation between interspecies could be preserved or broadened in the induced F(1). The use of DH inducer created special breeding resources for interspecific hybridization and distant hybridization of rapeseed while shortening time, improving efficiency, and providing a new insight into innovate breeding resources.