Molecular Diversity of Walnut (Juglans regia L.) Among Two Major Areas in Morocco in Contrast with Foreign Varieties

Abstract

In Morocco, walnut tree (Juglans regia L.) cultivation is ancestral with complicated misidentification and unknown local genetic diversity. Atlas Mountains host a rich walnut tree germplasm, which has arisen from seedlings. The use of molecular markers makes it possible to overcomes confusion usually encountered in phenotypic characterization, thereby elucidating the real genetic diversity magnitude. This study aimed to investigate the genetic relationships among 33 local walnut trees grown in two contrasted agroecosystems, while comparing them with 8 Bulgarian varieties belonging to an ex-situ collection, using ISSR markers. The use of 13 primers generated 120 reproducible ISSR markers, with 7 to 13 bands and an average of nine bands per primer. This number reflected the high level of polymorphism between genotypes revealed by the selected primers. The average polymorphism rate was 75.2%, with the polymorphic information content varying from 0.212 to 0.370 and with an average of 0.32. Genetic distances and the pairwise comparison showed that all pairs of genotypes are distinct using more than 10 markers with a maximum of 50 bands. The dendrogram showed an obvious phylo-geographic structuring and the differentiation of genotypes by origin area. The Bulgarian cultivars form distinct groups that confirms the specificity of the Moroccan walnut gene pool. However, the dendrogram obtained showed that the Moroccan genotypes are genetically close to a certain number of Bulgarian genotypes. This indicates that some Moroccan genotypes and the Bulgarian varieties could have a common ancestor.

Advances in genomics for diversity studies and trait improvement in temperate fruit and nut crops under changing climatic scenarios

“…In this study by using 13 primers, 120 ISSR markers (reproducible) were generated, demonstrating the high rate of polymorphism among genotypes with 7 to 13 bands and an average of nine bands per primer. According to these investigations, the overall polymorphism level (average) was 75.2%, with an average polymorphic informativeness content of 0.32 and a range of 0.212 to 0.370 ( Houmanat et al., 2020 ). From these studies, it was concluded that ISSR markers were found to be more systematic in measuring the genetic diversity of walnut genotypes among two major areas in Morocco in comparison with foreign varieties as reported by Houmanat et al.…”

Morphometric Traits and iPBS Based Molecular Characterizations of Walnut (Juglans regia L.) Genotypes

“…The phenological and morphological characters are rather affected by environmental conditions. So, during recent decades many studies have focused on morphological traits with molecular techniques, such as DNA-based markers SSR, ISSR, AFLP, RAPD, and SNP (Single-nucleotide polymorphism) to reveal genetic diversity, relationships among cultivars or genotypes, explain phylogenetically and origin in walnut (Fjellstrom et al, 1994;Nicese et al, 1998;Kafkas et al, 2005;Christopoulos et al, 2010;Orhan et al, 2020;Houmanata et al, 2021). The percentage polymorphism and the average polymorphic band per primer detected in our present results were higher than previously found by İpek et al (2018) and Doğan et al (2010).…”

Effects of Walnut Bark Extract on the Human Platelet Aggregation, Adhesion, and Plasmatic Coagulation In Vitro

“…In medicinal flora, Morocco is one of the most important diversities of the Mediterranean basin, particularly for tree species including olive, fig, and walnut [ 11 ]. The most important areas of walnut were identified in the Rif, High, and Medium Atlas mountains and in arid regions in Southeastern Morocco [ 12 ].…”