Abstract:

The method to construct Chinese Cabbage core germplasm based on four types of sampling proportion methods in group, six overall sampling scales and two sampling methods were studied in light of 1 651 accessions of Chinese cabbage germplasm and their data of 43 morphological characters in the national medium-term genebank of vegetable germplasm resources. The main results were as follows: The best proper sampling proportion within group was based on index of genetic diversity which enabled the sampled number or proportion from different groups tend to balance, and better maintained the variability of original collection .The index of genetic diversity of the core germplasm established according to the method of genetic diversity index proportion reached maximum and the ratio of phenotypic retained reached 98% when the overall sampling scale increased to 15%. Although the proportion of phenotypes retained nearly 100% and phenotypic variability changed little, the genetic diversity index of the core germplasm decreased accordingly when the overall sampling scale increased to over 20%. So 15% of the overall sampling sizes were more appropriate. In certain sampling proportion method and sampling scale, I, RPR and CV of the core germplasm constructed by cluster sampling was much higher than that by random sampling. Based on the optimized sampling scheme, the Chinese cabbage core gernplasm of 248 accessions of Chinese cabbage gernplasm were established.

Key words: Chinese cabbage, morphological data, core germplasm, sampling scale, sampling method