Assessment of genetic diversity in Iranian melon (Cucumis melo L.) landraces and hybrids using ISSR markers

Different species of Cucurbitaceae family are one of the most important sources of human food widespread in the world. One of the economically most important species of this family is melons (Cusumis melo L.) which are cross-pollinated and morphologically diverse plants. In the current investigation, genetic diversity of 11 Iranian landraces and 12 hybrid varieties of C. melo L. was assessed using 20 ISSR primers. The Twenty used ISSR primers generated 311 distinguishable and scorable loci, of which 52.26% were polymorphic. The highest values of heterozygosity (He) 0.135) and number of effective alleles (Ne) (1.23) observed for primer UBC820 while the lowest amount of those (0.031 and 1.058) was observed for primer UBC857. The average He for all studied genotypes was 0.155. The He value of hybrids was more than that for landraces. The highest value of He (0.177) obtained for landrace Zivari-shahrood (Zi-Sha), while landrace Tal-Shahrood (Ta-Sha) showed the lowest amount of He (0.118). Cluster analysis based on simple matching similarity coefficient using UPGMA algorithm grouped the genotypes in 7 groups. Population structure analysis using Bayes model confirmed the K 7, as the reliable value for the number of clusters. The hieghest value of Nei’s genetic distance observed between landrace Darghazi-tashkand (Dar-ta) and Durango hybrid. The landraces Darghazi-tashkand (Dar-ta) and Khatouni- Fariman (Kha-Far) had the lowest genetic distance. In conclusion, the current investigation demonstrated that ISSR markers might be useful in genetic diversity assessment of melons and obtained heterotic groups could be used in melons breeding programs.