Morphological and genetic analysis of a cleistogamous mutant in rapeseed (Brassica napus L.)

Cleistogamy, the trait of non-opening flowers, is considered to be beneficial as it reduces the threat of genetic contamination and gene flow from genetically modified varieties into other crops or native species. A cleistogamous mutant Zhong9-Clg obtained in the rapeseed cultivar Zhongshuang 9 population (Brassica napus L.) treated by ethylmethanesulfonate were investigated. Mutation had pronounced effect on petal and sepal epidermal cells resulting in the inhibition or delay of petal development, forming folded petals which ultimately resulted in cleistogamous flowers. Genetic investigation revealed that this trait was monogenic and the allele for cleistogamy was dominant. Most of the eight agronomic traits tested, including seed yield per plant, were not significantly different between the mutant and wild type plants. Fertility of the cleistogamous mutant Zhong9-Clg was not significantly affected by mutation. Our research findings will lay the foundation for the development of the cleistogamous varieties that could be used in controlling the gene flow in rapeseed in combination with other means of containment strategies.