Genetic Analysis Of Plants Regenerated From Microspores In Chinese Cabbage

Chinese cabbage, one of the most popular vegetables with abundant resources, has been intensively investigated for plant regeneration from the microspore culture. Microspore is mononuclear cell released from tetraploid after male gametophyte meitotic division, which can improve dormant gene's selection frequency and facilitate to select deseired traits from the doubled haploid. RAPD technology has been popularized for its simplicity, rapidity and non-specialty among different genera, and is extensively applied in research on plant genetic diversity and germlasm classification in lack of knowledge of genetic backgrounds.In this study, 50 Chinese cabbage plantlets were obtained derived from microspore culture, and RAPD and systemic clustering analysis of the genetic diversity was carried out.1 Process of embryogenesis during tissue culture was observed under Inversed , Microscope. The results showed several stages were involved in microsporesdevelopments, i.e. dyad, tetraploid, multi-cell proembryoid and cotyledonous embryoid. Three genotypes of more than 200 Chinese cabbage microspore plants including HY LB and KF were attained. And the plants were doubled in chromosomes, and transplanted onthe field.2 The results of self-pollination at flowering stage showed that HY HI are self-incompatible with low compatiblity. The compatible index was not high either during bud stage pollination. Only 43.75% of plants have the self-compatibilty index(above 5) .3 The genetic analysis showed that variation was 0.606 based on the data of 3 morphological characters of HY H2. Plant height, perimeter and compactness of leaf heads decrease genetic variations.4 Systemic clustering analysis was carried out among of Chinese cabbage with RAPD markers. DNA samples were amplified with 33 sets of primers. TheSO plants derived from 2 genotypes DNA samples were divided into two groups, Group one was consisted of 33 of HYHi , according H2 and HYFi, Group two was 17 of KF HI andKFFi.5 Analysis of Group One showed descendants were clustered with the according parent, indicating close genetic relationships, while plants derived from independent microspores showed far genetic distances. And total 206 distinct bands were obtained with 136 polymorphic bands (66.1%) . Analysis of Group Two showed total 200 distinct bands were obtained with 120 polymorphic bands (60%) .6 The 17 samples of HY H2 and HYF,, and The 17 of KF H, and KFF, were analysised with method of systemic clustering analysis and with method of principal coordinates analysis. The results showed, systemic clustering analyses were classified into 4 groups and 5 groups respectively. Principal coordinates analyses were classified into 3 groups and 4 groups. The results of two methods were coherent.