Genetic Diversity and Identity of Chinese Loquat Cultivars/Accessions (Eriobotrya japonica) Using Apple SSR Markers

Loquat (Eriobotrya japonica) is an underutilized fruit crop that originated in China and for which only a small number of molecular markers are available. This number can be increased by identifying apple SSRs that are transferable to loquat cultivars/accessions to provide new insight into the level of genetic diversity within loquat and synteny with apple. We evaluated 71 apple SSR markers distributed across 17 linkage groups, and identified 39 SSRs transferable to loquat. Testing 54 loquat accessions, from Japan, Spain, four provinces in China, and two wild species gave a total of 155 different alleles with a mean value of 3.38 per locus. The mean effective number of alleles was 2.21, and the mean observed heterozygosity was 0.47. These values indicate a high degree of genetic diversity in the set of Chinese loquat accessions analyzed. Unweighted pair-group method analysis based on simple matching coefficent clustered the accessions into two groups, cultivated and wild loquat. The cultivated loquat can be subdivided into three subgroups which generally reflect their geographic origin in China. The Spanish cultivars clustered with those of the Jiangsu and Zhejiang provinces. A core set of five SSR markers could distinguish most accessions.