Indian Journal of Plant Genetic Resources

Pinus gerardiana or chilogoza pine is a very important conifer species which is distributed very sparsely and is threatened due to reckless cone harvest leading to almost complete lack of natural regeneration. The present study was carried out to assess genetic variation among ten different populations of the species in Himachal Pradesh using isozymes. A total of nine isozyme loci were recorded for four enzyme systems and fifteen alleles were assigned for different isozymes. The isozyme loci such as PER-I, EST-II and AAT-II were the most variable in terms of allele frequency. For each locus one allele was most common, not only with respect to its frequency, in the population but also with respect to the number ofpopulations which contained it. The isozyme loci PER-II and NADH-I appeared heterozygous. Most of the genetic variation parameters showed a range of variation in different population and also revealed low variation in some of the isolated populations of P. gerardiana and perhaps is result of inbreeding insmall populations. On the basis of similarity coefficient and genetic distances it is concluded that various populations ofP. gerardiana differ substantially i.e. upto 7 per cent of total variation can be attributed to the population differences which is generally high for any conifer. It is also concluded that species is highly heterozygous in nature as indicated by negative F-statistics.