雄性榧树天然居群表型多样性及优株初选

  目的  探究雄性榧树Torreya grandis天然居群的表型多样性，初步筛选雄性优良单株，为科学配置优良授粉树和提高香榧T. grandis ‘Merrillii’种实产量和品质提供参考。  方法  以5个雄性榧树天然居群的121个单株为材料，对叶片单叶质量、叶形指数及雄球花单花质量、花形指数、花粉得率、花粉生活力等10个表型性状进行了分析，探讨其表型变异程度和变异规律，并初步筛选了雄性榧树优良单株。  结果  ①在居群间除了叶长和花粉得率有显著差异(P＜0.05)外，其他性状均无显著差异(P＞0.05)；在居群内10个表型性状都存在显著性差异，即居群内的变异大于居群间的变异，表明雄性榧树表型变异主要来源于居群内，人工选择要以单株选择为主。②10个表型性状中雄球花指标的变异系数大于叶片，且花粉生活力和花粉得率平均变异系数分别为42.36%和34.13%，变异较为丰富，因此授粉优树的选择可基于雄球花性状指标。③根据雄株雄球花性状指标综合筛选出了早、中、晚型36个优良单株，可在今后的选育和造林实践中应用。  结论  雄性榧树表型性状在居群内具有更加丰富的遗传多样性，在后期遗传改良中应重视群体内优良单株的选择，而球花大小、花粉生活力和花粉得率是榧树雄株进行优株初选的重要表型指标。图1表7参26

Phenotypic diversity of male cones and the selection of superior plants among male populations in Torreya grandis

  Objective  With the phenotypic diversity of male Torreya grandis populations explored and superior male individuals initially screened, this paper is aimed to provide a reference for the scientific configuration of superior pollinator trees so as to improve the actual yield and quality of T. grandis ‘Merrillii’.  Method  With 121 single plants selected from 5 natural male populations in T. grandis, an analysis was conducted of 10 phenotypic traits including single leaf weight, leaf shape index, weight of single male cone, cone shape index, percentage of pollen yield and pollen vitality, etc to study variation in phenotype, based on which superior male individuals were selected.  Result  (1) There were no significant differences (P＞0.05) between populations in all the traits except leaf length and percentage of pollen yield (P＜0.05), but there were significant differences in all 10 traits among individuals within each population, indicating that variation within a population is the main sources of phenotypic variation in male T. grandis and larger than that among populations, which means that artificial selection should be based on the selection of individuals. (2) Among the 10 phenotypic traits, coefficients of variation for male cones were larger than those for leaves with 42.36% and 34.13% as the coefficient of variation for the pollen vitality and pollen yield respectively, which indicates that the selection of superior male individuals should be based on the traits of male cones. (3) 36 superior early, interim and late flowering individuals were screened out according to traits of male cones, which could be used as reference for breeding and plantation in the future.  Conclusion  The phenotypic traits of male T. grandis demonstrate more significant genetic diversity within the populations, and the focus should be laid on the choice of superior individuals within populations in the attempt at the establishment of later genetic improvement strategy of T. grandis while cone shape index, percentage of pollen yield, pollen vitality are important phenotypic indexes for the primary selection of superior individual. Ch, 1 fig. 7 tab. 26 ref.]