Phenotypic and seed structural comparison in hybrids of different Brassica rapa and B. oleracea

Abstract

AbstractBrassica napus is an important oil species with short history and narrow genetic background. Interspecific hybrids from crosses between B. oleracea and different B. rapa were obtained. We found the hybrids with white petal resembling B. oleracea, the flavonoid and phenolic content decreased in hybrids, agreeing with the expressional changes of flavonoid biosynthesis genes. Seed coat of hybrids resembled diploid parents, or partly resembled to each parent with a clear outline. The palisade layer in hybrids was thicker than parents, with similar pigment accumulation as B. oleracea but more than B. rapa. Differentially sized protein bodies (PBs) were found in hybrids. The radical and inner cotyledon of all hybrids were identified with larger but less PBs than parents. The average size of PBs in outer cotyledon of resynthesized B. napus was also larger than parents, but the number of PBs was not significantly reduced. The phenotypic and seed structural variations after polyploidization of B. napus would be interesting for genetic broadening and breeding of rapeseed.