Analysis of genetic diversity of gac [Momordica cochinchinensis (Lour.) Spreng] in Southern Vietnam using fruit-morphological and microsatellite markers

Sweet gourd (Momordica cochinchinesis (Lour.) Spreng) (2n = 28) belongs to Cucurbitaceae family and is native to Southeast Asia as well as Vietnam. It is indigenous throughout Asia and being used as food and for medicinal purpose. The aim of this study was to estimate genetic diversity of gac accessions collected from Southern Vietnam based on 7 fruit-morphological traits and 10 SSR markers. The analysis of variance (ANOVA) revealed highly significant differences among 16 gac accessions. The gac accessions revealed difference in all fruit-morphological characters. Ten SSR primers showed high level of polymorphic fragments (100%). A total of 52 alleles were detected and the number of alleles per locus ranged from 2 to 8 with an average of 5.2 alleles per locus. The fragment size varied from 150 bp to 610 bp. The polymorphism information contents (PIC) of markers varied from 0.27 to 0.86 with an average of 0.58. Expected heterozygosity (H_E) ranged from 0.11 to 0.86 with a average of 0.40. The mean of observed heterozygosity (H_O) was 0.64 with ranging 0.38-0.94. Nei's genetic distance coefficient ranged between 0.0 and 1.0 and with the mean 0.79. Dendrogram based on UPGMA analysis grouped the 16 gac accessions into three main groups. Combination of fruit-morphological with molecular markers such as microsatellite markers gives a good observation of genetic diversity of gac accessions.