菜薹种质内不同大小群体问遗传多样性的RAPD鉴定和比较

为了了解菜薹种质内的遗传多样性，确定适宜的更新群体，从一份菜薹地方品种的200株群体中随机抽取10、15、20、25、30、35和．40株组成不同的群体，利用RAPD技术分析各自的多态位点数、计算多态位点百分率、遗传多样性指数和缺失位点数。通过对各参数的比较结果表明，该种质内单株间的遗传差异较大，大于30株的群体能代表200株群体的遗传多样性。在满足其完全随机交配的前提下，可视为更新的有效群体。根据更新时繁种群体应为有效群体2倍的原则，认为不小于60株的群体为菜薹种质更新比较适宜的群体。

RAPD Identification and Comparison of the Genetic Diversity among Different Populations Sampled from Same Accession of Flowering Chinese Cabbage (Brassica campestris L. Ssp.chinensis var. Utilis Tsen. Et. Lee)

In order to investigate genetic diversity in populations of Flowering Chinese Cabbage and screen suitable sample size for germplasm regeneration, different bulks with 10,15,20,25,30,35 and 40 plants were formed from an accession of 200 plants of Flowering Chinese Cabbage by randomly sampling. The number of polymorphic loci, the percentage of polymorphic loci, the genetic diversity index and the number of lack loci of different populations were analysed and calculated with RAPD technique. The results indicated that a sample of more than 30 plants could represent the genetic characteristics of a population of 200 plants. Based on the principle that the size of propagating population should double the size of effective one in germplasm regeneration, a sample of no less than 60 plants should be appropriate for regenerating Fowering Chinese Cabbage germplasm.