Polymorphism of male cones in populations of Pinus yunnanensis Franch.
云南松居群内雄球花多态性

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.