Study on genetic diversity of 33 walnut genotypes (Juglans regia) using morphological and pomological markers for introducing of superior genotypes

Document Type : Original Article


1 Associate Professor, Department of Horticultural Science and Landscape, Faculty of Agriculture, Malayer University

2 M.Sc. Student, Horticultural Science and Landscape, Faculty of Agriculture, Malayer University


Evaluation of genetic diversity among populations, cultivars and genotypes is the first step in breeding programs. For this reason, identification and introducing the superior genotypes is very important in development of improved walnut gardens. In the present study genetic diversity of 33 seed- genotype of walnut located in the Agriculture Research Station of Malayer University were evaluated using some morphological and pomological traits for identifying superior genotypes. Based on the results, a significant difference was found among different genotypes regarding the studied traits. Time of leaf bud burst in MKG112, MKG65 and MKG105 genotypes were later than other genotypes. The highest kernel percentage and kernel weight with 67.51% and 5.94 g were found in MSG15. The lowest shell weight with 3 g was observed in MKG82 genotype. Also, MKG105 genotype had the highest nut weight with 33.80 g. The highest (72.95%) and lowest (51.93%) oil percentage was related to MSG15 and MKG46 genotypes, respectively. Simple correlation coefficients between traits indicated the existence of significant, positive as well as negative correlations among some important vegetative, nut and kernel traits. Cluster analysis at Euclidean distance of 5, divided all genotypes into five main branches. Factor analysis reduced the assessed traits to 11 main factors justifying 71.01 % of total variation. Based on the results, genotypes including; MKG11, MKG12, MSG15, MKG16, MKG36, MKG41, MKG44, MKG45, MKG55, MKG65, MKG105, MKG111, MKG112 and MKG114 for some of the important traits such as nut and kernel characters, were better than other genotypes. These desirable genotypes can be used in walnut breeding programs.