Evaluation of genetic diversity among Iranian soft-seed pomegranate accessions by fruit characteristics and RAPD markers

Soft-seedness in pomegranate is a desirable trait for fresh consumption of this valuable fruit. At the main Iran pomegranate collection, 21 pomegranate accessions gathered from different parts of Iran are registered as soft-seed genotypes. The aim of this research was to study these soft-seed pomegranate accessions using fruit morphopomological traits and DNA markers to reveal their relatedness. Thirty-six fruit characteristics were measured in these accessions together with applying 29 random decamer primers already reported to be polymorphic on pomegranate. Factor analysis on mean values of fruit characteristics determined 10 main factors and applied for grouping of the accessions using Ward's method. Also 14 of the random primers showed good amplification and polymorphism on these samples, and a total of 43 RAPD markers were produced. Estimates of genetic similarity, using Jaccard's similarity coefficient, ranged from 0.13 to 1.0 using the RAPD data. Grouping based on the fruit traits compared with that based on RAPD data did not produce a significant correlation (r = −0.36). Morphometric measurements and sensory evaluation confirmed that some accessions are hard or semi-hard seeded. This study showed that information based on fruit characteristics and RAPD markers are complementary for genetic discrimination in soft-seed pomegranate accessions. This might be due to the high level of similarity between soft-seed pomegranate accessions.