GENETIC-STRUCTURE AND MATING SYSTEM IN TEAK (TECTONA-GRANDIS L-F) PROVENANCES

Genetic variability in teak has been analysed up to now quite exclusiv ely in provenance or progeny tests using quantitative traits. Few data were available on gene diversity revealed by genetic markers. This st udy dealt with analysis of 14 enzyme systems expressed in leaf parench yma of teak seedlings. Gene diversity was assessed in 9 populations in cluding 1 population which consisted of 10 open-pollinated progenies. These 10 progenies from an Indian stand served also for genetic analys is of isozyme patterns. Eighteen of the 20 putative loci investigated were polymorphic. A total of 80 alleles were scored at the polymorphic loci, up to 11 alleles were noticed at a polymorphic locus. At the Ad h locus, 4 of the 11 alleles were null alleles. The diploid status of the species was confirmed by expression patterns of isozymes. In the 9 populations, the polymorphic locus rate was on average 79% (at criter ion 95%). Considering polymorphic loci, the average number of alleles per locus was 2.8 and the observed heterozygosity 0.32. Populations sh owed a general lack of heterozygosity (average fixation index: 0.11). Outcrossing rate was assessed in the provenance consisting of 10 separ ated progenies, multilocus outcrossing rate based on 10 polymorphic lo ci was about 0.98, while average single locus outcrossing rate was 0.9 2. Mother trees showed negative fixation indices at each polymorphic l ocus. Genetic structure of progenies and of reproductive trees was the n discussed.