Genetic diversity based on morphological traits and germplasm conservation of walnut in Kashmir, Pakistan

Abstract

Persian walnut is an economically important nut crop of temperate regions of the world. In the present study 225 local walnut accessions from 37 sites of Azad Jammu and Kashmir were analysed for morphological traits to investigate variability and identify superior one. Nut length, nut weight, shell thickness and nut diameter varied from 20.87–47.34 mm, 6.44–17.7 g, 1.61–2.54 mm and 27.25–44.31 mm respectively. Kernel weight and percentage varied from 2.81–8.65 g and 32.53–77.34%. Data were analysed statistically using multivariate analysis such as Principal Components Analysis and Cluster Analysis. Pearson correlation coefficient among traits revealed a positively significant correlation between nut weight and nut thickness (r = 0.45987), kernel weight and nut weight (r = 0.94777), kernel% and nut thickness (r = 0.48346), shell thickness and kernel% (r = 0.21961), a negative correlation with significant differences was found between kernel weight and nut thickness (r = –0.40968), kernel% and nut length (r = –0.10844) and between kernel% and nut weight (r = –0.95209). The highest and most significant positive correlation (0.96024) was observed between kernel weight and kernel% and (r = 0.94777) between kernel weight and nut weight. A wide range of variability was observed among walnut accessions and BA2, BN2, CN3 and BN4 accessions are reported as superior and conserved for future breeding programs due to their distinct characteristics.