Research On Genetic Diversity And Molecular Identification Of Hybrid Purity Of Qingmaye Chinese Cabbage

Qingmaye Chinese cabbage(Brassica campestris L. ssp. pekinensis Olsson)play a particular and valuable role in Tianjin's resources. It is meaningful to study on genetic relationships and seed purity of hybrid among 42 accessions of Qingmaye Chinese cabbage for potential gene resources.This research mainly included: 42 accessions of Qingmaye Chinese cabbage cultivars were analyzed which origin and type were different to study the genetic background and genetic relationship and five Chinese hybrids and their parents were identified by RAPD makers. The main results were as follows:First: Genetic diversity in 42 accessions of Qingmaye Chinese cabbage was assessed using by AFLP makers, and the genetic relationship among accessions was revealed by cluster analysis. Five pairs of AFLP informative primers generated 124 bands in total and 89(71.8%) were polymorphic. The similarity measures based on the Jaccard coefficient by SPSS were calculated and their average value was 0.707, ranging from 0.469 to 0.977. The clustering tree based on the bontanical traits was congregated into three groups. The first group mostly originated from Tanggu and Xiqing district in Tianjin; the second group was involed by 7 materials, which were from the district of Tianjin; the third group from the Hebei; The forth goup mostly originated from the various regions of Tianjin and Hebei. The clustering tree based on the AFLP was congregated into three groups. The first group mostly originated from the various regions of Tianjin and Hebei; the second group mainly from the district of Tianjin; the third group from the Hebei. The study ended with indication that analysis of the genetic diversity of vegetable plants based on AFLP markers was more efficient and exact than those botanical traits. In addition, there was obvious difference in geographic relationship among the clustering results.Second: RAPD analysis was used to test seed purity of five commercial hybrids Chinese cabbage cultivars'Jinqiu78','Jinqiu65','Qiulv75','Qiulv60'and'Jinbai56'. Firstly, 27 random primers producing high and steady polymorphism, which had repeated 2 to 3 times, were selected form 82 primers. Then, 19 random primers selected form them were analyzed the five commercial hybrids. Results suggested that the primers named"51,53,54,57,58, 62,72"could produce both female and male parents specific markers respectively, and identified the five hybrid combination effectively. As follows: 1) 2 primers of complementary type(51,54) and 53 primer of partial P₂ for'JinQiu78'combination; 2) 2 primers of complementary type(54,62)and 51 primer of partial P₂ for'JinQiu65'combination; 3) 4 primers of complementary type(51,53,54,58) for'QiuLv75'combination; 4) 3 primers of complementary type(51,53,72)and 54 primer of partial P₂ for'QiuLv60'combination; 5) 4 primers of complementary type(51,53,57,58)and 54 primer of partial P1 for'JinBai56'combination.