Genetic Analysis And Preliminary Mapping On Wax In Purple-caitai

Purple-caitai, a kind of cabbage, is a variant of Brassica, and originate from the region of Yangtze in China. Purple-caitai not only has rich nutrition, containing high quality components, but also tastes crisp, refreshing, and distinctive, so it is deeply loved by people. According to phenotype of stem in the period of commodity maturity, it can be devieded into two types, wax and waxless purple-caitai. Wax purple-caitai has the advantage of vigorous growth, high yield and strong resistance. While waxless purple-caitai has the advantage of good commodity and cuticular waxless in spite of lower yield. Basing on the advantage that cuticular wax can improve the resistance of plants, molecular biology related to wax has become a hot spot.In this study, wax purple-caitai no.3and waxless purple-caitai DXW can be used as parents and they were hybridized into groups of six generations. According to six generations as material, we not only do the morphological observation about the cuticular wax on the surface of stem, but clarified the inheritance law of wax character in purple-caitai and researched preliminary location of the wax gene in purple-caitai. The main results were as follows:1. The morphological observation on the glossy purple-caitai no.3and the wax purple-caitai D×W was made. According to scan electron micrographs illustrate, the waxless purple-caitai no.3has nearly nothing cuticular wax crystalline on the surface and the wax crystals are extremely sparse and granular, while the wax purple-caitai D×W has dense vesture of wax crystalline on the surface and the wax crystals are mainly flaky and constitute irregular three-dimensional structure.2. According to investigate the presence of cuiticular wax on the stem, the F1that come from the reciprocal cross between the wax purple-caitai D×W and the waxless purple-caitai no.3have cuticular wax on the surface. The F2that come from the reciprocal cross F1selfing showed character separation, What is more, the result of chi-square test showed that the wax segregation accorded with the proportion of3:1. The BC1P2that come from backcross between F1and wax parent P2all express wax, while the BC1P1that come from backcross between F1and waxless parent P1express separation of wax and waxless, moreover the analysis of chi-square test showed that the wax segregation accorded with the proportion of1:1. According to all of these, the wax of purple-caitai is controlled by a dominant nuclear gene. 3. Using SSR techniques and bulked segregant analysis (BSA), The BC1P1were used as the mapping population. Two markers are linked to the wax gene, BnEMS0353and CB10081, with the genetic distance of5.5cMå'Œ34.8cM. In addition, the two markers locate on both sides of the target gene. After the Blast program, the wax gene of purple-caitai is preliminary located on A01.4. Using SSR markers newly developed and bulked segregant analysis (BSA), the target gene is mapped further. We found six markers that linked to the wax gene and initially mapped the wax gene between the UGBnM1048and UGBnM1336, with the genetic distance of2.8cM and1.8cM. After the Blast program, the wax gene is mapped on Scaffold11which is on chromosome A01of Brasscia rapa.5. Through a reverse validation, the three SSR primer about the candidate gene Bra013809already published in Chinese cabbage were not amplified polymorphic bands between the wax and waxless genetic pool from BC1P1. So it is speculated that the candidate gene Bra013809of the Chinese cabbage wax is not the wax gene of purple-caitai we are finding.