• Energy Research

The food needs for increasing population, climatic changes, urbanization and industrialization, along with the destruction of forests, are the main challenges of modern life. Therefore, it is very important to evaluate plant genetic resources in order to cope with these problems. Therefore, in this study, a set of ninety-one walnut (Juglans regia L.) accessions from Central Anatolia region, composed of seventy-four accessions and eight commercial cultivars from Turkey, and nine international reference cultivars, was analyzed using 45 SSR (Simple Sequence Repeats) markers to reveal the genetic diversity. SSR analysis identified 390 alleles for 91 accessions. The number of alleles per locus ranged from 3 to 19 alleles with a mean value of 9 alleles per locus. Genetic dissimilarity coefficients ranged from 0.03 to 0.68. The highest number of alleles was obtained from CUJRA212 locus (Na = 19). The values of polymorphism information content (PIC) ranged from 0.42 (JRHR222528) to 0.86 (CUJRA212) with a mean PIC value of 0.68. Genetic distances were estimated according to the UPGMA (Unweighted Pair Group Method with Arithmetic Average), Principal Coordinates (PCoA), and the Structure-based clustering. The UPGMA and Structure clustering of the accessions depicted five major clusters supporting the PCoA results. The dendrogram revealed the similarities and dissimilarities among the accessions by identifying five major clusters. Based on this study, SSR analyses indicate that Yozgat province has an important genetic diversity pool and rich genetic variance of walnuts.

Alternate bearing (AB) is of great importance in horticulture and leads to fluctuations in yield variation. Although AB is a natural phenomenon to optimize resource allocation and improve crop productivity and profitability in plants, understanding the factors that influence AB can help in implementing effective management strategies to reduce the negative effects and promote consistent and sustainable production. This study aimed to investigate the variation in carbohydrate levels in various tissues of both bearing and non-bearing pistachio (Pistacia vera L. cv Uzun) trees during different periods of growth development in two consecutive years to gain a deeper understanding of their potential contribution to AB. Twelve 34-year-old pistachio trees, consisting of six “ON” and six “OFF” year trees, were accidentally selected from a pistachio orchard. The “OFF” year trees were induced two years before sampling to be in the “OFF” year state by artificially removing flower buds. Sucrose was the main soluble sugar in the different parts of the pistachio tree studied. In general, the amount of sugar was higher in the non-bearing year than in the bearing year. It was found that non-structural carbohydrates of trees decreased between June and July, resulting in flower buds to abscise. The amount of carbohydrates decreased during nut development in “ON” trees, indicating the possible role of carbohydrates in AB.