| The vegetable craps of Chinese cabbage originated from China, which comprised non-heading Chinese cabbage and heading Chinese cabbage. It is the unique species with special tastes among all kinds of vegetable crops in the world and one of the earliest cultivated vegetables in China. Its germplasm resources are plentiful and have a wide-range of distribution. Understanding the relationships of different types of Chinese cabbage and their genetic diversity will benefit the effective collection, documentation and utilization of the germplasm and further improve the breeding work.DNA markers as a major technical method, can be used in analyzing of genetic diversity and genetic relationship in Brassica Campestris ssp. Chinensis germplasm resources. In breeding, the result of this study could be a strong assistance for identifying genetic relationship in parental lines, besides, it is also beneficial for minimizing the number of crossing combinations and enhancing the efficiency of breeding.In this study, AFLP and SRAP technique have been used to explore the genetic diversity and taxonomy of 115 Brassica Campestris ssp. Chinensis collected from 3 Units. 10 pairs of AFLP primer- combination and 28 pairs of SRAP primer-combination generating high polymorphism and powerful distinctiveness have been selected. Agronomic traits system clustering analysis was conducted based on leaf surface, leaf edge, leaf color, leaf shape, leaf firmness, petiole color, leaf trichomes, flowering time, self-compatibility, seed color. The categorization results of the two-marker system mentioned above and the agronomic trait analyzation system reached a consensus. All these results showed that AFLP and SRAP markers were effective and reliable in the study of the genetic diversity of Brassica Campestris ssp. Chinensis.Results:1. The primer combinations E+3/M+3 can amplify a proper number of bands and the AFLP fingerprinting was very clear after the sliver -staining.2. It was found that the number of amplified bands, with the 10 pairs of E+3/M+3 primer combinations, was between 15 to 46, the percentage of polymorphic bands was between 57% to 91%. E32M50 is the primer combination with highest efficiency, generating 46 fragments in which 42 are polymorphic fragments (91%). Through this combination, 115 materials can be distinguished from each other.3. The range of SRAP bands detected by individual pair of primer was from 20 to 29. The percentage of polymorphic bands was between 9.1%-31.8%.4. AFLP and SRAP technique have been used to explore the genetic diversity and taxonomy of 115 Brassica Campestris ssp. Chinensis. Chi-square distance and deviation square method were used in clustering analysis based on the 1-0 data results with the help of Data Processing System (DPS).5. The categorization results of the two-marker system mentioned above and the nagronomic trait analyzation system reached a consensus. The number of polymorphic fragment of AFLP is higher than those of SRAP, but SRAP marker with the merit of simple manipulation, lower cost and improved band articulation. All these results showed that AFLP and SRAP markers were effective and reliable in the study of the genetic diversity of Brassica Campestris ssp. Chinensis.
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