浙皖地理种源钩锥遗传多样性分析及选育策略研究

Genetic Diversity Analysis and Selective Breeding Strategy Research on Zhejiang and Anhui Geographic Provenances of Castanopsis tibetana

钩锥(Castanopsis tibetana Hance)为锥属(Castanopsis)高大乔木,具有材用、果用及观赏价值,其研究刚起步。为了制订该树种的选育策略,本研究基于钩锥同属或同科物种SSR引物,用筛选出的20对引物对‘浙皖龙泉’(LQ)及‘休宁’(XN)两个地理源钩锥半同胞家系及不同居群进行遗传多样性分析。结果发现,钩锥同属或同科物种间SSR引物的通用性较高;各遗传参数休宁的略大于龙泉,但二者差异不大;居群的遗传参数要大于半同胞家系,居群的等位基因数(Na)平均为3.85,有效等位基因数(Ne)平均为2.23,期望杂合度(He)平均为0.42,观测杂合度(Ho)平均为0.34,Shannon多样性指数(I)平均为0.79,主要变异在居群内;供试的材料无论在家系水平还是在居群水平均可按种源聚成二类。因此,该树种的选育应种源选择为先,在此基础上再基于生产目的进行优良单株的选择,同时因该树种分布范围广,因而要进行多点多年的引种对比试验。

Castanopsis tibetana is a tall tree species belonging to Castanopsis, which has the value in material,fruit and ornamentation. The study of this species has just started. In order to develop strategy for selective breeding of this species, 20 pairs of SSR primers were screened out of the SSR primers from other species which were in the same category or same family of C. tibetana. Then, the genetic diversity of C. tibetana half sib families and different populations from two geo-provenances, viz. Longquan of Zhejiang and Xiuning of Anhui, were analyzed. Results showed that the SSR primers had a high transferability between C. tibetana and other species of the same genus or same family; genetic parameters of Xiuning were a little bit higher in value than those of Longquan, but the diffrence was not significant; genetic parameters of populations were higher in value than those of families. The average values of Na, Ne, I, Ho, and He for populations were 3.85, 2.23, 0.79, 0.34, and 0.42,respectively, and main variation existed within populations; all the samples tested could be clustered into two groups based on provenances either in terms of families or populations. Therefore, the selection of provenances should be the first choice for this tree species, followed by elite individual trees for the purpose of production.Meanwhile, a test of multi-sites and comparison for introduction of this species should be performed for years because of a wide range of distribution of this species.