Screening melon ( Cucumis melo L. ) RIL population established for resistance to powdery mildew by different marker systems

The ISSR, SRAP, SSR, TRAP and SCAR markers were used to investigate the genetic relationship between parents as well as between parents and 138 genotypes of the RIL population established for resistance to the powdery mildew. A total of 12 polymorphic primers (14 polymorphic alleles) from 92 ISSR primers, 9 polymorphic primer combinations (11 polymorphic alleles) from 65 SRAP combinations, 22 polymorphic primers (44 polymorphic alleles) from 116 SSR primers, 5 polymorphic primer combinations (5 polymorphic alleles) from 26 TRAP combinations and 1 polymorphic primer (2 polymorphic alleles) from 5 SCAR primers were obtained. As a result of the analyses, clustering analyses were performed by UPGMA method, using similarity index and dendrograms were obtained. In the dendrogram created for the SSR marker system, the population was divided into two different groups, as TKU3 (female parent) in the first group and PMR6 (male parent) in the second group. For the TRAP and SRAP markers, the dendrograms were divided into two different groups. However, the SSR marker clearly distinguished individuals. ISSR and SCAR markers were not able to distinguish the differences between TKU3 and PMR6. When all markers were evaluated together, the similarity ratios ranged from 0 to 0,99, and the matrix correlation (r) was found to be 0,82. As a result of the markers evaluation together, the population was generally divided into two groups. In the first group, susceptible genotypes were included, and the closest genotypes were 0,98 genetically similar to H31, H32, H7, H8 and H4, H5 and H6, while in the second group resistant genotypes were included. T56 and T57 genotypes were found to be the closest to each other with a genetic similarity ratio of 0,98. In the second group the closest genotype to PMR6 was found to be Kül 14-1 (resistant) with a genetic similarity rate of 0,95. These findings were supported by the results of dendrogram and PCO obtained by Neighbour-Joining method. In the results of the study, evaluating marker systems alone, except SSR, was not sufficient to detect susceptible and resistant individuals. For this reason, it is recommended that codominant and dominant marker systems should be used together to obtain more accurate results in future studies.