Collecting and identification of Willows (Salix spp) accessions of Kurdistan and collection establishment

In order to Collecting and identification of Willows of Kurdistan and collection establishment of endemic and exotic willows this trial was conducted. After identification of natural willow lands of different areas of Kurdistan and labeling of elite mother trees, those cuttings have been taken and planted in nursery condition in Sanandaj. These practices repeated for 3 years (2000-2002). Transplanting of nine uniform 2/2 saplings (biannual root and shoot) and planting of them in collection were conducted in early April for 3 stages (2002- 2004). In collection, each plot (willow clone) involved nine saplings that were planted as 3Ã_3 with 3mÃ_3m . In 2005-2007, some morphological, phonological and quantitative traits such as trunk diameter in 1.3cm height (D) and tree height (H) and missing percentage due to drought stress in 2007 were evaluated. According to our evaluation, willows species were distributed in nearly all area of Kurdistan province. There is about 3000km rivers in length (main and sub branches) and willows growth in approximately all river lands. This experiment resulted in collecting and establishing of 58 accessions of willow. Furthermore, seven exotic willow clones (from main willow collection of Research Institute of Forests and Rangelands of Iran) have added to collection in 2005. The collected accessions divided in 5 species as Salix excelsa (38.6%), Salix alba (36.8%), Salix triandra (17.5%), Salix aegyptica (5.3%) and Salix babylonica (1.7%). Therefore, Salix excelsa, Salix alba and Salix triandra involved over than 90% of willow population of Kurdistan province and were general species of willow in there. According to results, the best time for cutting and planting of them in nursery was early of March. The mentioned accessions and species have been described based on the phonological, botanical and morphological characteristics in Sanandaj conditions. Analysis of variance (completely randomized design) showed significant differences (pâ_¤0.01) among in same years old accessions for trunk diameter in 1.3cm height (D) and tree height (H) and missing percentage due to drought stress of 2007. In addition, diameter and height growth of 7 years old accessions belonged to Salix excelsa (14.08 cm and 7.90m for diameter and height growth respectively) and species Salix triandra accessions (12.91 cm and 7.09m for diameter and height growth respectively) were higher than Salix alba accessions (12.50 cm and 6.43m for diameter and height growth respectively). The 7 years old accessions showed the least missing percentage due to drought stress (11.55%) while the 5 years old accessions showed the highest missing percentage in collection. Thus, age increasing resulted in increasing of drought stress tolerance. Among 7 years old accessions, those belonged to Salix babylonica (with 22.22% missing percentage) showed the least tolerance while those belonged to Salix excelsa (with 4.17 missing percentage) showed the highest tolerance to drought stress.