Quantitative trait locus (QTL) mapping of resistance genes to Botrytis cinerea using SSR markers in grape (Vitis vinifera L.)

Grape (Vitis vinifera L.) is a fruit that has economically to assess many such as table grapes, dried, wine, fruit juice and molassesh. Turkey is ranked 5 th in table grape production in the world due to very suitable ecological conditions for viticulture. One of the most important fungal problems that limit the production of graps is gray mold (Botrytis cinerea). Today, many fungicides are used to management with B. cinerea, nowadays however; it is getting very difficult since it becomes resistance to fungicides. Therefore, it is important to breed with resistant varieties and breeding programs should be established. However, there is no marker associated with resistance to lead mold disease that can be used in the breeding program yet. The most efficient usage area of molecular markers identification of quantitative characters loci (QTL) which managed multiple genes with complex inheritance. When the molecular marker or markers linked to the studied resistance loci are developed, resistant and susceptible plants can be separated from each other quickly and safely at all stages of breeding. Until today , no genetic mapping studies have been carried out on the resistance to gray mold in grapes and no molecular markers have been developed. In our study, F1 genotypes obtained from Kyoho X Yalova İncisi hybrids were used as the mapping population. 350 SSR marker were used to investigate the genetic relationship between parents and individuals on 99 genotypes of the F1 population established for resistance to the gray mold. Of the markers, 19 polymorphic, 313 monomorphic, while amplification could not be achieved from 18 of them. It was determined that a total of 44 alleles were obtained from 19 polymorphic SSR primers and all of these alleles were polymorphic. The average number of alleles per marker and the average number of polymorphic alleles were found to be two. The polymorphism rate of marker is 100% and the PIC value is 0.71. As a result of the analyses, clustering analyses were performed with the UPGMA (Unweighted Pair Group Method Using Arithmetic Average) method using the similarity index and dendograms were obtained. In the dendogram created in the SSR marker system, the population was divided into two different groups. Yalova pearl (mother) was in the first group and Kyoho (father) was in the second group. According to the similarity coefficient of Dice (1945), the similarity ratios varied between 0.38 and 0.92, and the matrix correlation (r) was found to be 0.58. These results were supported by the dendogram obtained by Neighbor-Joining method and PCO (principal coordinate analysis). A total of 17 markers showing Yalova pearl (mother) and Kyoho (father) segregation were used in Kruskal-Wallis analyses and the markers significantly associated with disease resistance were determined (p<0.05). As a result, a total of four markers were found to be associated with disease resistance. QTLs with an effect level of 20-24% were identified.