Assessment of Variability and Genetic Factors among High Heritable Traits of Juglans regia (Walnut) from North Western Himalayan Regions

Juglans regia L. (Walnut) generally renowned as English Walnut or Persian Walnut. It is popular for its quality edible nuts and strong wood resulted into cultivation in wide area. Walnut is a prime member of Juglandaceae family with sporophytic chromosome number 2n = 2x = 32. The Union Territory of Jammu & Kashmir had a significant walnut gene pool represented by seedling trees for decades. The region’s rich walnut diversity in terms of morphology, phenology, biochemical and biological traits is due to presence of the large variability of native Walnut trees. This largely resulted from cross-pollination and seedling propagation. This study was conducted during 2021–2022 in JKUT and Himachal Pradesh. It was based on data collected during a preliminary survey during the current research work. As part of our research, the variability and genetic parameters of nut characters were evaluated to identify and marking of elite walnut genotypes owning superior characteristics and high-quality traits and also to understand the existing genetic variability in walnut germplasm. The data were collected from one hundred two (102) walnut trees located in various geographical regions of JKUT and Himachal Pradesh. We also calculated phenotypic and genotypic variances (PCV and GCV), heritability (in a broad sense), and expected genetic gain (GG percentage of the mean) on the basis of data collected during the research work and resulted into the high heritability (h²) and high to moderate genetic gain (GG) in the walnut species from JKUT and Himachal Pradesh.