Research Information System
SILVAE GENETICA, vol.48, no.6, pp.293-302, 1999 (SCI-Expanded)
The nature and extent of variation in certain crown (crown diameter, live crown ratio, crown shape index) and branching traits (branch angles, number of growth cycles, length of the longest branch) of Pinus brutia TEN. were investigated in this study. The data were collected destructively by thinning a provenance-progeny trial, first at age 13 and then at age 17 years. There were six natural populations each represented by 10 open-pollinated families, and each family by 10 half-sibs in the experiment. Populations were significantly different for all the branching and crown traits. Similarly, there were significant differences among families within populations for most traits. Populations from higher altitudes showed relatively wider branch angles, shorter branches and longer and narrower crowns. Crowns get narrower (r= -0.59, p<0.0001) and longer (r=0.45, p<0.0001) with the increase of altitude of origins. Families with straighter stems had narrower crowns (r= -0.72, p<0.0001). The percent of genetic variation due to populations in crown and branching traits was considerable, ranging from 2.4% (crown diameter) to 24.5% (crown shape index). Variance components due to families were in general below 10% for each trait, showing increasing tendency with age. Individual heritabilities for the branching traits were moderately high, ranging from 0.23 to 0.53. On the other band, heritabilities for crown traits were weak at age 13, but for crown diameter and for crown shape index were comparatively high at age 17. The results indicated that combined population, family ana within-family selection for branching and crown traits would result in considerable gain in Pinus brutia.