Variation evaluation in growth traits of selected Salix alba genotypes in cold desert of Himachal Pradesh

Salix alba Linn is a fast-growing multi-purpose tree species that provides livelihood support to natives of the cold desert region of Himachal Pradesh. Considering the importance of this species, the present study was carried out to identify the superior genotypes in terms of growth performance for plantations in the cold desert. Five populations of the species in the Spiti valley of Lahaul and Spiti, Himachal Pradesh were surveyed and based on growth parameters including height and stem diameter, trees free from diseases and insect pest attacks were selected as candidate plus trees (CPTs). Cuttings from the selected CPTs were raised in the nursery and their field trials were laid out at Tabo, Lahaul and Spiti, Himachal Pradesh. The highest height and diameter were attained by the genotype G1T3 selected from the Gue1 population in Spiti valley. After the second year of growth, the height increment was maximum for G1T3, whereas, the performance of PT2 (from Poh population) was found to be better in terms of diameter growth, with a 4.328 and 3.024 mm increment in collar diameter (CD) and diameter at breast height (DBH) respectively. Based on the growth parameters, CPTs, namely G1T3, G2T13, G2T7, PT1, PT2 and GU2T1 were found to be superior over check. All the genotypes were clustered into two major groups. The first group was mainly composed of genotypes belonging to the Gue1, Gue2 and Poh populations, except GU2T1, whereas, the second cluster was mainly composed of genotypes belonging to the Gulling population. The role of ecological adaptation of the genotypes in the clustering pattern was clearly visible.