Genetic Diversity Assessment of Citrus Accessions Grown in Indonesia Using Molecular Markers

The assessment of genetic diversity is crucial in citrus improvement programs that represents the relationship among genotypes, thus determining an effective plant breeding program. A molecular assessment of 52 collected citrus accessions based on ISSR and SSR was conducted at the ICSFRI in 2020. Based on 4 ISSR primers and 3 SSR primers, the citrus genotypes were grouped into 6 major clusters. Cluster I has the largest 25 members, while Cluster II, III, IV, V and VI have 5, 2, 2, 4 and 13 accession members, respectively. Members of Cluster I are the majority in the mandarin type with spheroids fruit shape with truncate on the fruit top. Cluster II contains citrus accessions from naturally occurring hybrids, while orange accession members of Cluster III are originally grown in different climates. Cluster IV and V members are connected to a common ancestor, Citrus aurantifolia and Citrus limonia. At the same time, Cluster VI is a pumelo group that contains members of Citrus maxima. Clustering based on molecular markers (ISSR and SSR) resulting in this study is useful in citrus breeding programs in Indonesia and other countries. The genetic distance of the parents affects the heterosis effect of the progeny.