Determination of loci related to some biochemical parameters using association mapping method in pistachio (Pistacia vera L.)

Pistachio is a species in the Anacardiceae family within the genus Pistacia and only species with economic value among the species in the genus Pistacia. Its Latin name is Pistacia vera L. and a type of hard-shelled fruit that is very important for human health in terms of nutritional values. The main factors limiting pistachio breeding studies are periodicity, a very long juvenile period, and its dioecious flower nature phenomena. In order to overcome such limits in breeding programs, marker assisted selection is very significant. In the present study, it was aimed to detect loci associated with fruit quality traits by using a total of 150 female cultivars and genotypes. Firstly, phenolic compound (gallic acid, catechin, quercetin, naringenin, chlorogenic acid, ferulic acid, p-coumaric, rutin, luteolin), sugar (fructose, glucose, sucrose), color (L,a,b,C,hº) and chlorophyll (chlorophyll a, chlorophyll b, total chlorophyll) analyzes were performed using pistachio nuts harvested in 2018 and 2020 production years. SNP loci associated with a total of 30 phenotypic data calculated using genotypic data of a total of 150 pistachio cultivars and genotypes were detected by MLM (mixed linear model) approach using the GAPIT function of the R program. Minor allele frequency was applied as MAF=0.05. Bonferroni test was applied as p=0.01 to determine important relationships, and after the analysis, highly associated loci at p=10-4 level were applied. As a result of the association mapping, a total of 249 linked loci were identified in both years, 65,386 loci in 2018, 51,467 loci in 2020, associated with a total of 11 phenotypic traits. Once the obtained SNP loci are verified, they can be used in marker assisted selection studies in pistachio breeding programs in terms of these traits.