Characteristics Analysis of F(1) Hybrids between Genetically Modified Brassica napus and B. rapa

A number of studies have been conducted on hybridization between transgenic Brassica napus and B. rapa or backcross of F(1) hybrid to their parents. However, trait changes must be analyzed to evaluate hybrid sustainability in nature. In the present study, B. rapa and transgenic (BrAGL20) B. napus were hybridized to verify the early flowering phenomenon of F(1) hybrids, and F(1) hybrid traits were analyzed to predict their impact on sustainability. Flowering of F(1) hybrid has been induced slightly later than that of the transgenic B. napus, but flowering was available in the greenhouse without low temperature treatment to young plant, similar to the transgenic B. napus. It is because the BrAGL20 gene has been transferred from transgenic B. napus to F(1) hybrid. The size of F(1) hybrid seeds was intermediate between those of B. rapa and transgenic B. napus, and ~40% of F(1) pollen exhibited abnormal size and morphology. The form of the F(1) stomata was also intermediate between that of B. rapa and transgenic B. napus, and the number of stomata was close to the parental mean. Among various fatty acids, the content of erucic acid exhibited the greatest change, owing to the polymorphism of parental FATTY ACID ELONGASE 1 alleles. Furthermore, F(2) hybrids could not be obtained. However, BC(1) progeny were obtained by hand pollination of B. rapa with F(1) hybrid pollen, with an outcrossing rate of 50%.