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Populus tomento a was crossed with P. tremuloidis, P grandiden ata, P. lba × P. grandidentata and P. alba × Ulmus s . ta pumila in order to maintain its rapid growth and high wood quality and improve its resistance to cold. Two methods were used to increase the germination rate from 1.5% to 41.1% and the remaining rate from 1.7% to 44.2%. Forty crossing combinations were conducted and 2 744 hybrid seedlings were obtained. MX. t4 × P grandiden ata (G-1-58), MX3 × P. tremuloidis (T-44-60), MX2 × P. tremuloidis (l-13-87-37) and MX2 × (P. alba × P. grandidentata) were regarded as superior combinations after analysis and selection. Thirty seedlings of these combinations and 11 triploid seedlings identified by counting their chromosomes were selected as super plants.
Populus tomento a was crossed with P. tremuloidis, P grandiden ata, P. lba × P. grandidentata and P. alba × Ulmus s. Ta pumila in order to maintain its rapid growth and high wood quality and improve its resistance to cold. Two Methods were used to increase the germination rate from 1.5% to 41.1% and the remaining rate from 1.7% to 44.2%. Forty crossing combinations were conducted and 2 744 hybrid seedlings were obtained. MX. t4 × P grandiden ata (G-1- 58), MX3 × P. tremuloidis (T-44-60), MX2 × P. tremuloidis (1-13-87-37) and MX2 × (P. alba × P. grandidentata) were distinguished as superior combinations after analysis and selection. Thirty seedlings of these combinations and 11 triploid seedlings identified by counting their chromosomes were selected as super plants.