关键词: 杜仲, 核心种质, SSR

Abstract: [Objective] Core collection of Eucommia ulmoides was constructed to retrench germplasm resources in the gene pool, which will provide a theoretical basis for protecting, utilizing and studying germplasm resources of E. ulmoides.[Method] Based on allele number maximization strategy,core collection of E. ulmoides was constructed from 887 total collections, which located in 54 distribution area, by using nine SSR primers and bioinformatics software. Core collection of E. ulmoides was assessed by the number of allele (n), average number of allele(N_a), average effective number of allele (N_e), average Shannon's information index (I), Nei's diversity index (H), average genotype number (N_g), average polymorphism information content (PIC), and their retaining ratio. The representative of the core collection to the total collection was confirmed with t-test and PCoA analysis.[Result] 107 alleles(n) were detected in 9 SSR primer pairs, the average of N_e was 5.096. High genetic diversity was revealed in the germplasm resources of E. ulmoides(I=1.812, H=0.925). 189 of 887 core collections were obtained based on allele number maximization strategy, suggesting that the 21.3% of the collection samples contained 100%number of alleles. The retaining ratio of N_a, N_e, I,H, N_g and PIC of nine SSR locus was 100%, 116.5%, 108.7%, 101.5%, 100%, 103.3%, respectively. t-test analysis suggested that there was no significant correlation between the six evaluation parameters of core collection and total collection. This result was further confirmed by the PCoA analysis. 698 of 887 reserve collections were obtained based on allele number maximization strategy, suggesting that the 78.7% of the collection samples contained 86.9% number of allele. The retaining ratio of N_a, N_e, I, H, N_g and PIC of the nine SSR locus was 86.9%, 95.7%, 96.7%, 99.4%, 77%, 99%, respectively. t-test analysis suggested that there was no significant correlation between the six evaluation parameters of reserve collection and total collection.[Conclusion] The core collection of E. ulmoides was well constructed, which contained all the alleles and genotypes. There was no significant difference in six evaluation parameters of the core collection and total collection. Moreover, the core collection and total collection samples had the similar structure in the distribution map. All the seven evaluation parameters of the core collection were higher than the reserve collection. Therefore, the core collection should be priority option in protecting germplasm resources and constructing breeding population of E. ulmoides. This study laid a foundation for the identification of favorable genes and breeding of new varieties of E. ulmoides.

Key words: Eucommia ulmoides, core collection, SSR