Genetic Test of Open-Pollinated Larix kaempferi Families and Selection for the Second Generation Elite Trees in Northern Sub-Tropical Alpine Area

The genetic variation of growth traits of 119 Larix kaempferi families including 1 962 individuals from 5 open- pollinated progeny test forests were analyzed to select the second generation elite trees for the second generation orchard in northern sub-tropical alpine region of Hubei Province. The results showed there was significant difference in growth traits among different families. Individual and family heritability of DBH,height and volume ranged from 0. 18 to 0. 73,0. 17 to 0. 59,0. 19 to 0. 78,and 0. 34 to 0. 80,0. 42 to 0. 79,0. 18 to 0. 81,respectively. Individual heritability of the three traits usually was lower than their family heritability. Individual breeding values were predicted by using the best linear prediction approach. Comparison between combined selection and family /within-family selection showed that the second generation elite tree populations that were established by combined selection had a higher genetic diversity than that established by family /within-family selection,but the two selection methods got nearly common expected genetic gains. In terms integration of high genetic gain and genetic diversity,elite trees chosen by combined selection were more suitable to establish the advanced-generation seed orchard. As a result,total 137 individuals derived from 49 different families were selected as the second generation elite trees by combined selection; and the expected genetic gains of 5 progeny test stands were 26% ,98. 3% ,42. 9% ,24% and 56. 4% ,respectively.