Variation among poplar clones for growth and crown traits under field conditions at two sites of North-western India

We evaluated the growth and crown traits of 36 poplar clones at two distinct agro-climatic regions of Punjab （Ludhiana and Bathinda） in northwestern India, following randomized block design with three replications and plot size of four trees. Significant differences among clones （p〈0.001） were observed for diameter at breast height （DBH）, tree height, volume, crown width and number of branches under both the site conditions. Clones ‘G-3’, ‘25-N’ and ‘41-N’ at Ludhiana and ‘G-3’, ‘RD-01’ and ‘S7C8’ at Bathinda were found to be superior for volume production. All growth and crown traits registered significantly higher values at Ludhiana in comparison to those at Bathinda. Clone site interaction was also significant （p〈0.001）. For volume, clones ‘L-62/84’, ‘113520’, ‘25-N’ and ‘S4C2’ witnessed huge fluctuations in ranking between sites. The correlations between growth traits were positive and highly significant （p〈0.001） at both sites. The clonal mean heritability was moderate for DBH and volume both at Ludhiana （0.61–0.66） and Bathinda （0.61–0.62）. Across sites, the genetic advance was the highest for volume （49.76%） and the lowest （6.50%） in case of height.