Evaluation and Classification of 48 poplar (Populus spp.) ‎clones by seedling leaf and wood yield characteristics

The aim of the study was to investigate leaf characteristics of 48 poplar (Populus spp.) clones and their relationships with seedlings wood yield. The trial was conducted in 2003 at Zalleh Nursery of Sanandaj City, under Completely Randomized statistical design (CRD) with nine replicates, using one year old (1/1) seedlings. Five leaves were sampled from the middle level of each seedling crown at early August. (five leaves for each seedling clone at each replicate), air dried and measured in laboratory. The measured leaf parameters were: weight, surface area, lenghth, width, length / width ratio, total seedling grean surface area (leaf surface area × leaf number), main nerve number, petiole length, lamina weight, lamina / total leaf weight  ratio, seedling Leaves number and weight of surface area unit. The seedlings height, diameter and wood yield were measured as well. NOVA, regression and cluster statistical methods were applied for data analysis and classification. The results showed that the regression MS of leaf characteristics on seedling wood yield was significant at α = 0.01. there were hight and positive correlations between leaf characteristics, particularly surface area, weight and total grean surface area and seedling wood yield at α =0.01 (r = 0.343, 0. 309 and 0.343, respectively). There were hight diversity among poplar species and clones in view point of leaf characteristice. Mean leaf surface area and weight and seedling total green area of the clones was 46.8 cm2, 0.4 g and 1724.5 cm2, respectively, whereas for the five superior clones was 81.85 cm2, 0.8 g and 2314.43 cm2, repectively. The highest leaf surface area and total leaf number belonged to the superior clones of P. deltoides and P. nigra, respectively. Cluster analysis based on leaf characteristics and both leaf and stem cheight, diameter and yield parameters, showed that the leaf characteristics classified the clones botanically whereas the leaf and srtem parameters classified them botanically and silviculturally, particularly the wood production potential characteristics. Using the last applied method of classification, the 48 poplar clones were classified at six groups as follows: P. alba (very low wood yield), deltoides 1 (high yield), euramericana (low to medium yield), P. nigra (medium yiald), P. euphratica (very low yield) and P. deltoides 63 (very hight yield).