Characterization and selection of thin-shelled walnut (Juglans regia L.) genotypes of Mustang, Nepal

Abstract

Walnut (Juglans regia L.) of seedling origin creates large variability within this crop. A research study was carried out at Directorate of Agricultural Research, Lumle, Kaski and Marpha, Mustang to characterize and deciphers the variability of thin-shelled walnut for further selection, conservation and variety registration. Walnut orchard of Mustang district was surveyed in March, 2018 and 50 walnut trees were labeled according to its flowering and flushing time. 36 accessions of thin-shelled walnut were characterized on 17 different parameters regarding growth habit, bearing habit, fruit and kernel characteristics. Around 88.89% trees exhibited terminal fruiting habit and remaining showed lateral fruiting habit. Three type of tree shape was noticed as spreading round, semi-erect and erect. Huge variation in nut shape was observed having 50% trees were with circular nuts. Four types of shell strength was recorded; 11.11% accessions having papery shell, 27.78% having weak shell, 47.22% having intermediate shell and 13.88 having strong shell strength. Average nut yield of trees ranged from 15-75 kg with an average of 26.67 kg. Nut weighted from 5.96-18.99 g with an average of 11.14 g. Kernel weight ranged from 2.8-8.92 g. More than 50% shelling was recorded in 13 accessions. The kernel quality of 14 accessions (out of 36) showed 5 rank (Excellent quality); and remaining 22 accessions showed 4 rank (Good quality). Based on this characterization, 13 accessions were selected and recommended for further multiplication and variety registration.