Evaluation of Genetic Distance and Similarity among Native Genotypes of Seeded Watermelon (Citrullus lanatus var. citroides) in the Khorasan Region Using Microsatellite Markers

Citrullus lanatus var. citroides is one of the Khorasan region's major rainfed and cash crops. It is typically grown on marginal lands and mostly dependent on rainfall. Microsatellite markers were therefore employed in this study to determine the genetic diversity among the genotypes from these important production zones in the provinces of Razavi and North Khorasan in order to be used in the future breeding programs of this crop. With the aid of 15 pairs of microsatellite primers (SSR), the genetic diversity among 17 genotypes of C. Lanatus var. citroides collected from various parts of Khorasan province along with one edible variety (Ed) was examined in this study. These markers allowed for the DNA fingerprinting of genotypes, in which 11 markers were polymorphic. In two cases, the polymerase chain reaction (PCR) products were monomorphic and shared by all genotypes, but in the other two, no detectable PCR product was observed. The range of the polymorphic information content (PIC) was 0.13 to 0.86. The genetic similarity among genotypes was determined to be between 15% and 55% using the Jaccard similarity matrix in the NTSYS program (Ver. 2.02). Three major groups were formed by clustering 17 genotypes using the UPGMA method and the Jaccard similarity coefficient. These findings demonstrated that the Ed variety was classified into a different group due to its significant genetic differences from other seeded watermelon genotypes. While verifying the significant amount of genotype diversity, the results of principal component analysis (PCA) of the data were highly in agreement with those of cluster analysis, making the similarities of genetic relationships very clear. This study could be significant in terms of the first steps toward identifying genetic diversity and maintaining genetic reserves in native genotypes of seeded watermelon for future breeding purposes.