An SSR-Based Assessment of Genetic Diversity in 16 Tomato (Lycopersicon esculentum) Lines and it's Correlation with Heterosis

Prediction of superior crosses before their being performed, and an evaluation of the progeny in the field can lead to an increase in the efficiency of hybrid-seed production. A significant number of studies, during recent decades, have proved a positive relationship between heterosis and the genetic distance evaluated through molecular markers. SSR markers were employed to study the relationship as well as the genetic distances between the lines, and to select the appropriate parents for production of hybrid varieries from 16 evaluated tomatos. PCR amplification was performed using 10 primer pairs which resulted in appropriate and scorable patterns for the 16 evaluated genotypes. A total of 35 alleles were observed for the 10 SSR primers, ranging from 2 to 7 alleles per primer (with an average of 3.5). Maximum and minimum PIC values were calculated to be 0.84 and 0.30, respectively. The results indicated that SSR markers are efficient in polymorphism detection as well as in evaluation of genetic distance among tomato lines, and can be applied as accurate indicators in analysis of genetic relationships among genotypes. However, through our study on 63 hybrids, no significant relationship was observed between the SSR-evaluated genetic distances and the degree of heterosis concerning yield, fruit size, fruit count, and longevity.