Ssr Molecular Marker Of Self-Incompatibility Gene In’Aijiaohuang’,Acultivar Of Non-Heading Chinese Cabbage

Non-heading Chinese cabbage (Brassica campestris ssp. chinensis Makino) is one of the basic diploids in Brassica of Brassicaceae, which is an important vegetable in south China and plays an important role in our daily life. Non-heading Chinese cabbage is a cross-pollinated crop and has self-incomaptibility. In this study, hybrid combinations were made between self-incompatible line’210’and self-compatible line’002’. The corresponding F2segregating population was gained, and then used for genetic analysis of self-incompatibility and screening of SSR markers. The results are as follows:1. Two hybrid combinations F2(’002’X’210’) and F2(’210’X’002’) were used to study the inherence of self-incompatibility character in non-heading Chinese cabbage. Self-incompatibility data of F2population was statistically analysed and Chi-squared (χ2) tests were applied. The F2population presented traits separation,78F2(’002’X’210’) generated57self-compatible plants and21self-incompatible plants,158F2(’210’X’002’) generated113self-compatible plants and45self-incompatible plants. The segregation ratio between compatibility and incompatibility was3:1. Thus, the self-incompatible trait of non-heading Chinese cabbage was controlled by a pair of recessive alleles.2. In order to determine molecular markers that linked to self-incompatible genes in non-heading Chinese cabbage,352pairs of SSR primers were randomly adopted to amplify the DNA fragments from parents and F2(’210’X’002’) segregating population. Results revealed that21pairs of SSR primers showed steady polymorphism in parents, and these primers were6%in the total primers. Then, we screened158F2(’210’X’002’) plants, and three of the21pairs of SSR markers, Nal2E02, KBRH138G23and sR6688, were proved to tightly link to self-incompatible genes in non-heading Chinese cabbage. Through Mapmaker3.0software, we identified that genetic distance linked to self-incompatibility were3.08cM,5.35cM and12.91cM, respectively.3. On the basis of the screened molecular marker Nal2E02, MiroSatellite (MISA) and Primer3.0software were used for developing SSR markers that close to Nal2E02and in the range of3cM. Finally, we determined22SSR markers that presented polymorphism in parents and F2(’210’X’002’) segregation population. The22SSR markers were all amplified and produced clear DNA bands in parents, displaying an effective primers ratio with100%.,5of the22SSR primers could produced steady DNA polymorphism in parents, and was22.7%in the total primers. By using these5pairs of SSR polymorphism primers for screen in158F2(’210’X’002’) plants, we determined one SSR marker BrSS15that tightly linked to self-incompatible gene in non-heading Chinese cabbage. Through Mapmaker3.0software,0.49cM genetic distance was identified. This could be helpful for the molecular marker-assisted selection (MAS) of self-incompatible breeding and make it possible to localize and clone the self-incompatible genes.