Studies On The Genetic Diversity Of Clonal Seed Orchard Of Masson Pine And The Parentage Constituent Of Its Open-pollination Progeny

Seed orchard served as the bridge of breeding between the forest breeding and forest production is the most important population of seed production. The genetic diversity of its offspring will directly affect their stability and adaptability of forest population.Clones in seed orchard and their open-pollination seeds of Pinus massoniona Lamb, in Wuyi forestry farm, Fujian Province were studied by microsatellite (SSR) markers. The genetic diversity of both the parentage and their progenies was compared and paternity analyses of its progenies were also conducted. The main results were as follows.1 11 polymorphic SSR primers were selected from 163 used in other tree species amplified and analysized, the number of alleles per locus varied from 3 to 20, and 6.8182 on average.2 Parentage population showed a high genetic diversity. PIC of parentage population was calculated to be 0.5483, which was similar to that of massonion pine and other natural species. Ho and He were 0:3436 and 0.5506 on average respectively. Fit was 0.3819 on average. The effects of genetic drift on population disequilibrium could be neglected becauseof Nm=1.0367>1.3 Compared with the parentage population, there was no significant decrease in genetic diversity of the progeny population. F was 0.0079, close to zero, indicating no significant differences existing between the heterozygote and the homozygote of the offsprings. Fit was 0.0413, showing that the progeny population was closer to the Hardy- Weinberg equilibrium. It was presumably relevant to the randomly mating among the clones.4 Paternity analysis indicated that the parentage number of the progenies of the three maternal trees were all about 40, however, significant differences could be found in the parentiny components. Only 6 of 126 candidate parenity could pollinate with all the three maternal trees and 24 of them could pollinate with two of the three maternal trees.5 The origins of the parentiny varied and the same paretiny origins contributing to one maternal tree simultaneously have not been found.6 About 27.08%~48.96% pollen was contributed by 5%~15% candidate parenity, and one candidate parenity produced the largest amount of pollen. Although the contribution ratio of85%~95% candidate parenity ranged from 1% to 2%, relatively low, the candidate parenityprovided the progeny with genetic diversity. No significant correlation between the pollen contribution rates and the pollen amount of the candidate parenity was observed.7 Pollen contamination from the surrounding stands was observed during the parentiny analysis. 7 alleles from 6 different SSR locus were revealed only existing in the 27 progeny. Pollen contamination ratio was up to 9.44%.8. It was observed that about 2%~3% of the pronegies wre empty seeds and monster seedings which was probably caused by the self-pollination of the maternal trees.The paternities of all of the progenies could not be distinguished by only 11 SSR markers because of a numerous clones in seed orchard. More SSR markers or new study and analysis method sould be used to resolve this problem.