The strategy for maintaining genetic integrity of soybean germplasms - selecting pure lines based on SSR markers.

Objective The objective of the study is to identify the purity of soybean cultivars using SSR markers for efficiently keeping the genetic integrity of germplasm during germplasm conservation.Method The purity of 2 794 soybean cultivars or lines was analyzed by utilizing 59 SSR markers.Result 90.1% of soybean accessions had high purity,which indicated that most of them could be easily used in the breeding and researches.277 accessions with low purity were identified.Among them,94.2% were landraces,accounting for 10.5% of total landraces(2 475).t test also showed that the homozygosity of landraces was significantly lower than that of cultivars or lines.Conclusion The population size should be kept larger during the propagation for those lower purity accessions compared to high purity accessions,otherwise the low frequent genotypes were easy to be lost.In order to lower the cost of propagation and convenient utilization,it is strongly recommended that pure lines should be selected for the low purity accessions based on the molecular markers,and some accessions from provinces,such as Hubei,Sichuan,Jiangsu,etc.,should be put on the priority list.