Morphological and molecular evaluation of diversity in individuals obtained by intra-species hybridization in almond (Prunus dulcis L.)

Türkiye is the homeland of many plant species and has a significant genetic diversity. It is seen that different natural almond species grown in the region were included in the breeding research conducted on almonds, which is one of these critical species. In this study, natural almond genotypes grown in Türkiye and different commercial foreign-origin almond cultivar and genotypes obtained from intraspecies hybridization were evaluated morphologically and molecularly. In the hybrid genotypes obtained, plant growth was determined as weak, medium, and strong; plant habitus was upright, upright to spreading, spreading, and drooping; anthocyanin coloration was determined as light, medium, and strong; shoot pubescence was weak and strong, leaf blade/leaf width ratio was determined as medium and high. To determine the genetic diversity of parent plants and hybrid genotypes molecularly, 10 different inter simple sequence repeat (ISSR) primers were used, a total of 99 scoreable bands, 84 of which were determined as polymorphic. According to the unweighted pair group method with arithmetic means (UPGMA), the similarity index varied between 0.67 and 0.97, and two different main groups were formed in the dendrogram. Ninety-eight of 141 hybrid genotypes are in the first group. Genotypes Texas × A1-10 and Texas × A4-4 were included in the first group with a similarity index of 0.97. 100% polymorphism was determined in five different ISSR primers, and 80% or higher polymorphism was determined in seven of 10 primers. This group includes genotypes obtained from combinations using the Texas cultivar, mainly depending on the parent's parents. In the second leading group, there are 34 different hybrid individuals with mother and father parents. The results obtained would guide researchers in almond breeding programs.