Abstract:
The aim of the study was to compare the genetic variability within F1-progeny populations of Aleppo pine, growing under extreme environmental condition such as drought, with the genetic variability in the parental natural populations. Two different methods were used: Protein polymorphism by means of starch gel electrophoresis of enzymes, and genomic DNA polymorphism by means of the RAPD and PCR methods. The result of isoenzyme analysis showed that the number of alleles per locus (A/L) in populations ranged from 1.3 to 1.7. Percent polymorphic loci (P%) ranged between 12 and 44% in the natural populations and between 40 and 48% in the populations growing under the stressful environment. Mean value P% increases from 31% in natural forests to 44% in the Yatir forest populations and, consequently, the mean observed heterozygosity increased from 0.096 to 0.152. RAPD analysis showed that gene diversity (h) rose from between 0.264 and 0.316 in the natural populations to between 0.406 and 0.431 in Yatir. The calculated linear regression between allozyme heterozygosity and gene diversity resulted in r = 0.690, p < 0.001, n = 5. The Yatir afforestation can be looked upon as peripheral populations under selection pressure that eliminates homozygous and favors heterozygous genomes. This forest should be treated as a biogenetic resource for seed material.