Evaluation of inter and intra-specific hybridization of clones of Populus nigraand P. deltoides

The aim of this study was to use the potential of productive cultivars to produce new hybrids and to evaluate the morphological and anatomical traits of hybrid seedlings between P. nigra and P. deltoides.In the present project, the male and female bases of the superior clones of Populus nigra and Populus deltoides were used, which had a high performance in terms of wood production and proper trunk quality, and were introduced to the implementation department. In winter 2018, the flowering branches of the base material with flower-bearing buds about 60–100 cm in length were collected from the end branches of the tree and planted in 20 litre plastic pots consisting of mixture of soil, sand and well-rotted cattle manure. To prepare pollen grains, a sufficient number of flowering branches were separated from the male branches of each of P. nigra and P. deltoides species and placed in a container of water and the pollen was collected by opening the male flower catkins.Pollination was achieved by lightly dusting the receptive flowers with a camel-hair brush. Catkins were collected from the branches when capsules mature and all of sterilized hybrid and open pollination capsules were cultured on Half-MS medium without hormone in the form of splitting. Produced plantlets taller than 1 to 2 cm in size were transferred to jiffypots with a mixture of sterilized perlite and peat moss and sand and kept in greenhouse and the characteristics of the percentage of contamination, height of plantlets and the number of plantlets transferred to jiffypots were recorded. The hybrid seedlings were transferred to large pots after gradual adaptation, and then they were evaluated based on quantitative traits such as height, collar diameter, branch and quantitative characteristics and anatomy of leaves after two years. The results showed that the highest catkins height, number and weight of capsules were in open pollinated cross. A total of 28 progeny were obtained from Populus different crossings. The highest stem height in crosses of PD♀xPS♂ (P. deltoides Marquette x P. deltoides Samsun) and PD♀xPB♂ (P. deltoides Marquette x P. nigra betulifolia 17/13), the maximum branch angle, leaf area and specific leaf area in open pollinated cross of PD♀ (P. deltoides Marquette) was observed.