云南松居群内雄球花多态性

本文观察和统计了滇中地区云南松居群内雄球花多态性。 分别统计了当年生新梢上雄球花出现百分率、每个新梢下部聚生的雄球花数、雄球花的色彩、长度和直径。试图揭示云南松居群间和居群内雄球花的变异式样及其分布频率，探讨其变异形成的原因、保持机制和适应意义。研究表明，云南松居群内雄球花多态性显著，居群间多型性也较明显。云南松居群内雄球花多态性是国产松属中最丰富的，也是松属植物中所少见的。雄球花出现百分率、新梢下部聚生的雄球花数、雄球花的大小和色彩等性状，均受多基因控制，呈现连续性变异；云南松居群具有较高的遗传多样性和杂合度是其雄球花多态性和多型性丰富的遗传基础。杂合有利性是造成云南松多态性，特别是平衡多态性的重要原因，同时也使多态性得以保持。云南松林木分布生态环境条件的异质性本身也能导致平衡多态现象。云南松雄球花的变异性与生态环境和林木的年龄相关联，更与居群和林木的遗传结构密切相关。在云南松林木育种和造林过程中，应重视杂种优势和杂合有利性的利用。

Polymorphism of male cones in populations of Pinus yunnanensis Franch.

This paper deals with the polymorphism of male cones in the populations of Pinus yunnanensis Franch. from the central region of Yunnan. The morphological characters of male cones were statistically analyzed in the sampled populations.Male cone characters were observed and their polymorphism was described in the populations. As a result, male cones were shown highly polymorphic in the populations and the polytypism between the populations was obvious in P.yunnanensis .In the populations, the fertility, colour, number and size of male cone are controlled by multigene,and the variation of these characters appear continuous.The polymorphism and polytypism of male cones are based upon the rich genetic diversity and high heterozygosity among individuals and populations of P. yunnanensis . The heterozygous advantage and environmental heterogeneity are both important factors which cause and maintain the balanced polymorphism and herozygosity within population. The reproducibility of male cones is correlated with the habitat and wood age,and closely correlated to the genetic structure of individual and population of P. yunnanensis. It is important to utilize the hybrid vigor and heterozygous advantage in forest breeding and platation.