Genetic variability, correlation and path-coefficient studies among Persian walnut (Juglans regia) genotypes

The present study was conducted during 2015 and 2016 at ICAR-CITH, Rangreth, Srinagar to corroborate genetic variability among walnut genotypes and determine the potential traits for selection of superior genotypes. Genetic variability in any crop is a pre-requisite to initiate the breeding programme for the selection of superior entries over the existing cultivars. The efficiency of selection largely depends upon the magnitude of the genetic variability present in the plant population. Thus, large genetic variability offers better scope for the crop improvement. The experimental material comprised 136 walnut genotypes. Nut samples of each genotype were collected randomly in five replications and each replication consisted of five nuts. Quantitative traits were recorded as per walnut descriptors developed by IPGRI. The highly significant differences (P = 0.01) existed between genotypes for the nut and kernel traits studied. The range of some economically important traits varied widely for nut weight (6.08–24.23 g), kernel weight (3.30–11.16 g), and kernel recovery (36.27–60.19 %). The estimates of GCV and PCV were very high for nut weight (25.07, 26.05 respectively) and kernel weight (23.59, 25.35 respectively) indicating the importance of these traits in selection of superior genotypes. Trait association analysis also revealed mutual relationships and degree of interrelationships among all the nut and kernel traits. Thus, ample genetic variability observed among the studied genotypes for nut and kernel traits indicated effectiveness of direct selection for improvement of these commercially important traits.