title: Adaptive differentiation in seedling traits in a hybrid pine species complex, Pinus densata and its parental species, on the Tibetan Plateau.
abstract: Evidence from molecular genetics demonstrates that Pinus densata is a natural homoploid hybrid originating from the parent species Pinus tabuliformis and Pinus yunnanensis, and ecological selection may have played a role in the speciation of P. densata. However, data on differentiation in adaptive traits in the species complex are scarce. In this study, we performed a common garden test on 16 seedling traits to examine the differences between P. densata and its parental species in a high altitude environment. We found that among the 16 analyzed traits, 15 were significantly different among the species. Pinus tabuliformis had much earlier bud set and a relatively higher bud set ratio but poorer seedling growth, and P. yunnanensis had opposite responses for the same traits. P. densata had the greatest fitness with higher viability and growth rates than the parents. The relatively high genetic contribution of seedling traits among populations suggested that within each species the evolutionary background is complex. The correlations between the seedling traits of a population within a species and the environmental factors indicated different impacts of the environment on species evolution. The winter temperature is among the most important climate factors that affected the fitness of the three pine species. Our investigation provides empirical evidence on adaptive differentiation among this pine species complex at seedling stages.
authors.affiliation: State Engineering Laboratory of Forest Tree Breeding, Key Laboratory of Genetic and Breeding in Forest Trees and Ornamental Plants, Beijing Forestry University, Beijing, China; College of Biology Sciences and Technology, Beijing Forestry University, Beijing, China.
authors.forename: Jingxiang
authors.initials: J
authors.lastname: Meng
authors.affiliation: State Engineering Laboratory of Forest Tree Breeding, Key Laboratory of Genetic and Breeding in Forest Trees and Ornamental Plants, Beijing Forestry University, Beijing, China; College of Biology Sciences and Technology, Beijing Forestry University, Beijing, China.
authors.forename: Jian-Feng
authors.initials: JF
authors.lastname: Mao
authors.affiliation: State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, Chinese Academy of Sciences, Beijing, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Zhao
authors.affiliation: State Engineering Laboratory of Forest Tree Breeding, Key Laboratory of Genetic and Breeding in Forest Trees and Ornamental Plants, Beijing Forestry University, Beijing, China; College of Biology Sciences and Technology, Beijing Forestry University, Beijing, China.
authors.forename: Fangqian
authors.initials: F
authors.lastname: Xing
authors.affiliation: State Engineering Laboratory of Forest Tree Breeding, Key Laboratory of Genetic and Breeding in Forest Trees and Ornamental Plants, Beijing Forestry University, Beijing, China; College of Biology Sciences and Technology, Beijing Forestry University, Beijing, China.
authors.forename: Xinyu
authors.initials: X
authors.lastname: Chen
authors.affiliation: College of Resources and Environment, College of Agriculture and Animal Husbandry of Tibet University, Linzhi, Tibet, China.
authors.forename: Hao
authors.initials: H
authors.lastname: Liu
authors.affiliation: College of Resources and Environment, College of Agriculture and Animal Husbandry of Tibet University, Linzhi, Tibet, China.
authors.forename: Zhen
authors.initials: Z
authors.lastname: Xing
authors.affiliation: Department of Ecology and Environmental Science, Umeå University, Umeå, Sweden.
authors.forename: Xiao-Ru
authors.initials: XR
authors.lastname: Wang
authors.affiliation: State Engineering Laboratory of Forest Tree Breeding, Key Laboratory of Genetic and Breeding in Forest Trees and Ornamental Plants, Beijing Forestry University, Beijing, China; College of Biology Sciences and Technology, Beijing Forestry University, Beijing, China.
authors.forename: Yue
authors.initials: Y
authors.lastname: Li
mesh_terms: D000222:Adaptation, Physiological; D019143:Evolution, Molecular; D017343:Genes, Plant; D049810:Genetic Speciation; D010641:Phenotype; D010802:Phylogeny; D028223:Pinus / Q000235:genetics / Q000254:growth & development*; D036226:Seedlings; D013045:Species Specificity; D018609:Tibet