Study on parental selection strategies of high generation seed orchard of Pinus tabuliformis

Objective Through the comparison and evaluation of two parental selection strategies in advanced generation seed orchard of Pinus tabuliformis, it provides a scientific basis for the parental selection strategy of advanced generation high-yield and stable-yield of P. tabuliformis.

Method Selecting the open-pollinated progeny test forest of the first-generation seed orchard of P. tabuliformis in Shangzhuang, Xi County, Shanxi Province of northern China, as the base population. The genetic variation of growth traits in 42 half-sib families of P. tabuliformis was analyzed, the parents of the second generation seed orchard of P. tabuliformis were selected by the combined selection strategy and the direct selection strategy of optimal individual, the average growth and average expected genetic gain of each trait of the superior individuals screened by the two selection strategies were compared and analyzed.

Result There were significant differences (P < 0.01) in DBH, tree height and volume growth among and within half-sib families of P. tabuliformis. The combined selection strategy and the direct selection strategy of optimal individual separately screened 30 superior individuals, of which 19 were identical and 11 were different. The average DBH, tree height and volume growth of 11 unique superior individuals screened by the direct selection strategy of optimal individual were 7.72%, 18.56% and 31.01% higher than that of the combined selection strategy, respectively, and the average DBH, tree height and volume expected genetic gain of 30 superior individuals screened by the direct selection strategy of optimal individual were 15.52%, 121.78% and 29.38% higher than that of the combined selection strategy, respectively. Different from the combined selection strategy of selecting one superior individual for each elite family, among the 30 superior individuals selected by the direct selection strategy of optimal individual, 29 superior individuals belonged to 19 elite families, and 1 superior individual (D12) belonged to the non-elite family.

Conclusion The combined selection strategy will lead to the loss of some superior individual resources, and the direct selection strategy of optimal individual is more suitable for screening the parental materials of advanced generation seed orchard of P. tabuliformis.