Assessment of genetic diversity and relationships among Coix lacryma-jobi accessions using microsatellite markers

The present study describes the assessment of genetic diversity and relationships among 79 Job's tears (Coix lacrymajobi L.) accessions collected from China and Korea using 17 microsatellite markers. A total of 57 alleles were detected with an average of 3.4 alleles per locus. A high frequency of rare alleles (36.3 %) was observed within the collection. Values for observed (H(O)), expected heterozygosity (H(E)) and Shannon's information index (I) within the analysis ranged from 0.00 (GBssrJT183) to 0.81 (GBssrJT130), from 0.01 (GBssrJT170) to 0.65 (GBssrJT130) and from 0.034 (GBssrJt170) to 1.13 (GBssrJT130), respectively. The locus GBJT130 was the most informative marker with the highest values for observed and effective alleles as well as for H(O), H(E) and I. Based on the UPGMA algorithm, the majority of the Chinese accessions grouped in one cluster, whereas all the Korean accessions grouped together in a separate cluster, indicating that Chinese accessions are genetically quite distinct from Korean accessions. No relation between genetic relatedness among Job's tears accessions and their place of collection was observed. Chinese accessions exhibited greater within population polymorphism (P = 95 %, H(E) = 0.30, I = 0.52) than the accessions from Korea (P = 68 %, H(E) = 0.13, I =0.24), indicating their potentiality as a reservoir of novel alleles for crop improvement. However, in general the low diversity within each population indicates a narrow genetic base within our collection.