STRUCTURE OF ECOLOGICAL-GENETIC VARIABILITY OF LARIX SIBRICA LDB AT THE NORTHERN LIMIT OF ITS RANGE

The authors studied the structure of ecological-genetic variability of Larix sibirica Ldb. by means of seed-by-seed analysis of the traits o f plantlets raised in controlled conditions. Samples from tundra open forests and taiga communities in Southern Yamal with contrasting ecolo gical conditions served as the material for analysis. The portion of v ariance between samples is equal to 6.6% for the trait of the plantlet s' average length and unreliable for the other traits studied. The add itive genotypic component for the studied traits is 14-15% of the over all variance. A significant component of ''genotype-environment'' inte raction was revealed, indicating the seeds' different reactions to the conditions in which the plantlets are raised. In this case, in sample s from tundra open forests there is a group of trees the seeds of whic h produce plantlets that are indifferent to the effect of an environme nt that inhibits growth processes. The appearance of groups of individ uals with increased resistance to unfavorable factors may possibly be explained by processes of adaptation to pessimal conditions of existen ce at the forest's polar boundary.