Abstract:

【Objective】 The population structure and genetic diversity of mini core collection of cultivated soybean in China were studied in order to provide a theoretical basis for broadening the genetic base of soybean cultivars, identifying genes interested by breeders and improving varieties. 【Method】 The mini core collections of cultivated soybean in China including 248 accessions supplemented by 28 provinces were employed for SSR analysis using 100 SSR polymorphic primer pairs to detect the population structure and genetic diversity. The PowerMarker Version 3.25 software package was used to make statistics of the number of alleles, average alleles, specific alleles and polymorphic information content. Neighbor-joining tree of mini core collection of cultivated soybean in China was revealed by using similarity coefficients based on genetic distance. Structure 2.2 software was used to evaluate the population structure of mini core collection of cultivated soybean in China. 【Result】 All of the 100 SSR loci were polymorphic across the 248 accessions and a total of 1 460 alleles were detected. The average number of alleles per locus was 14.6, ranging from 2 to 33. The average polymorphic information content (PIC) per locus was 0.743 with a range of 0.158-0.932. There was no clear genetic structure according to the Log probability of data, LnP(D). The true population structure of mini core collection of cultivated soybean in China existed at K equals to 3 through calculation of the ?K. Analysis on eco-geographical types and cultivar types suggested that the accessions from the same origin trended to be divided into the same group. But a few accessions from the same origin were divided into different groups. The specific alleles existed among different eco-geographical origin types and different cultivar types. 【Conclusion】 The genetic diversity level of mini core collection of cultivated soybean in China is much higher which can be used to broaden the genetic base of soybean. More complementary alleles and specific alleles exist among different eco-geographical origin types and different cultivar types, which can be used for germplasm innovation and improvement. Clear population structure exist in mini core collection of cultivated soybean in China which has provided theoretical guidelines for using of mini core collection in soybean breeding program.

Key words: cultivated soybean (Glycine max), mini core collection, population structure, genetic diversity