Abstract: 【Objective】 Assessing the genetic diversity of peanut mini core collection in ICRISAT and analyzing their genetic relationships among various groups of taxonomy, and verifying the fitness of traditionally botanical taxonomic system under cultivated peanut were carried out in the study, which could provide essential information for the exploration and utilization of ICRISAT peanut mini core collection. 【Method】 One hundred and sixty-eight peanut accessions from 42 counties of five continents were employed for SSR analysis using 27 polymorphic primer pairs in this study. Three-dimensional PCA graphs was conducted and drawn in NTSYS-pc V 2.0 statistical package. Parameters of genetic diversity (Nei78 genetic distances, et al.) were proceeded in Popgene V1.32 statistical package. The dendrogram of UPGMA method were drawn in MEGA3.1 statistical package. 【Result】 One hundred and fifteen polymorphic bands were amplified using 27 SSR primer pairs with unambiguous unique polymorphic bands. In average, 4.2930 alleles were observed, 65.49% of which was effective alleles (2.7931) in each SSR primer pair. PM137, 16C6, 14H6, 8D9 and 7G02 were the most effective SSR pairs, I value of which was over 1.5, alleles of which was over 5, effective alleles of which was over 3.7. SSR alleles were uniformly distributed among botanical taxon units in cultivated peanut. For ssp. fastigiata var. fastigiata, genetic diversity of germplasm from North America and India were lower, and that from South America showed higher. For ssp. fastigiata var. vulgaris, genetic diversity of germplasm from North America and Europe was lower, and that from South America and Africa was higher. For ssp. hypogaea var. hypogaea, genetic diversity of germplasm from North America was lower, and that from South America and Africa and USA was higher. So, genetic diversity of peanut germplasm from South America was abundant, which conformed that peanut originates in South America. Four taxonomic clusters were detected in ICRISAT mini core peanut collection by using PCA analysis. Gene pool “hypogaea” mainly consisted of var. hypogaea, gene pool “vulgaris” mainly consisted of var. vulgaris, while gene pool “fastigiata 1” and “fastigiata 2”mainly consisted of var. fastigiata. Nei’78 genetic distance among botanical taxon based groups of peanut genetic resources ranged from 16.336-23.607 cM. Five large cluster groups were identified based on the UPGMA dendrogram. Group 1 equals to “vulgaris” gene pool; Group 3 equals to “fastigiata 1”and “fastigiata 2” gene pool; and Group 4 equals to “hypogaea” gene pools; Group 2 and 5 stands for var. peruviana and var. aequatoriana respectively. The UPGMA clustering results generally support the PCA clustering results. 【Conclusion】 There were significant differences among most botanical groups in ICRISAT mini core collection, with clear separation of four gene pools for genetic diversity structure. The research results partially support the traditional botanical taxonomy under A. hypogaea L. In order to broaden the genetic bases of peanut breeding, the genetic potentials in the ICRISAT mini core collection should be thoroughly exploited.

Key words: peanut (Arachis hypogaea L.), SSR, genetic diversity, core collection