Search

Developing late-leafing genotypes is crucial for mitigating the impact of late-spring frosts in walnut cultivation. Marker-assisted selection (MAS) offers a rapid screening approach for walnut populations in breeding programs, addressing the long breeding cycle. This study aimed to validate Turkish molecular markers associated with leafing date in the Iranian walnut populations and to implement MAS to identify late-leafing genotypes. Two polymorphic SSR primers, 'JRHR209732' and 'CUJ-RBO12', were validated using 14 early- and late-leafing cultivars/genotypes. MAS was then implemented for a population of 91 Iranian walnuts from a breeding program. The results indicated the effective differentiation of the Iranian population using the markers from Turkey, suggesting genetic similarity between the walnut populations of the two countries. Furthermore, alleles with band sizes of 277 and 115 were associated with late-leafing, while band sizes of 289 and 92 indicated early-leafing. Phenological data over three consecutive years, along with SSR analysis, confirmed the validation and implementation of MAS. The SSR analysis identified 14 alleles across all accessions, with an average of 7 alleles per locus. High leafing time variation was observed in the studied population, and cluster analysis identified four major clusters, revealing similarities and dissimilarities among the accessions. Finally, genotypes 'Ch35T12', 'ChLa1', 'ChFr2', 'ChFr3', 'Ped35T1', 'Ped35T4', 'PedLa1', 'PedLa3', 'PedOp1', and 'ChPed2' were identified as late-leafing genotypes based on screening with late-leaf alleles. [ABSTRACT FROM AUTHOR]

Iran is one of the two major centres of Pistacia diversity and the main producer of pistachios in the world. About 282 Iranian pistachio genotypes (Pistacia spp.), together with 22 foreign cultivars (P. vera), were genotyped using 10 simple sequence repeat (SSR) markers to analyse the genetic diversity and relationships among Pistacia species and cultivars. The results revealed that the genetic diversity within P. atlantica subsp. kurdica was considerably lower than in P. vera or P. khinjuk. Principal coordinate analysis revealed a clear separation between the different Pistacia spices, as well as between the Iranian and foreign cultivars. AMOVA analysis showed that the variation between the species, between different populations, and within populations accounted for 41, 9, and 50% of the total variation, respectively. The results demonstrated that the study of genetic diversity and relationships among Pistacia species and cultivars using SSR markers provides important information for the collection and conservation of pistachio germplasm. In addition, the Iranian cultivars had a broader genetic background than that of the foreign cultivars. Thus, they are very important for genetic conservation and the planning of future breeding programmes. We also determined the different levels of genetic diversity that exist between and within the species and populations and showed that gene flow occurs between the Iranian cultivars and wild-type P. vera populations. The study provides practical information that policy-makers and scientists can apply to the conservation and sustainable use of all the species studied. [ABSTRACT FROM AUTHOR]