Inheritance pattern of wood traits, especially heartwood/ sapwood percentage and specific gravity and interactions of wood traits with other growth traits were investigated in a 27-year-old half-sib progeny trial of teak. Wood traits showed highly significant variation for specific gravity, heartwood and sapwood percentage at family level. There was non-significant family vs. replication variation for these traits. Among the growth traits, there was significant variation for height and girth. Families and individual trees showed varying levels of heritability. Among the growth traits, height showed high heritability (individual tree heritability, h2 (i) = 34.3%; family heritability, h2 (f ) = 34.1%) followed by girth (h2 (i) = 19.4%; h2 (f ) = 31.4%). Among the wood traits, maximum heritability values were obtained for sapwood percentage (h2 (i) = 76.6%; h2 (f ) = 70.7%) and heartwood percentage (h2 (i) = 76.9%; h2 (f ) = 69.7%). Specific gravity exhibited heritability values of 29.1 and 41.8%, at individual tree and family level, respectively. Family heritability was higher than single-tree heritability for specific gravity; single-tree heritability exceeded family heritability for heartwood percentage. Specific gravity exhibited significant positive genotypic correlation with heartwood percentage suggesting that improvement in heartwood percentage would lead to a correlated improvement in specific gravity. Heartwood percentage showed significant positive correlation with growth traits viz., height and girth. Some of the families showed good GCA for growth and wood traits investigated. The good general combiners identified in the present study can be used for establishment of advanced generation seed orchards and breeding arboreta for improvement of teak for specific or combination of above traits.

Carbonic anhydrase (CA, EC: 4.2.1.1) activity in teak (Tectona grandis L.f.) was studied to determine its characteristics, kinetics and isozyme patterns. We also investigated effects of leaf age, plant age and genotype on CA activity and gas exchange parameters. Carbonic anhydrase extracted from leaves in 12 mM veronal buffer, pH 7.8, had a K(m) for CO(2) of 15.20 mM and a V(max) of 35,448 U mg(-1) chlorophyll min(-1), which values declined by 50 and 70%, respectively, after 1 week of storage at 4 degrees C. A 15% native polyacrylamide gel revealed the absence of CA isozymes in teak, with only a single CA band of 45 kD molecular mass observed across 10 segregating half-sib families and groups of trees ranging in age from 10 to 25 years. Activity remained stable during the first month in storage at 0 degrees C, but gradually declined to 25% of the initial value after 1 year in storage. During the period of active growth (February-May), maximal CA activity was observed in fully expanded and illuminated leaves. Significant variation was observed in CA activity across 10 1-year-old half-sib families and 21 5-year-old half-sib families. There was a positive correlation between CA activity and photosynthetic rate in a population of 10-year-old trees (P < 0.005). Positive correlations between CA activity and photosynthetic rate were found in 10 of 21 5-year-old half-sib families (P < 0.005 to P < 0.05), which showed greater diversity in CA activity than in photosynthetic characteristics. Thus, CA may serve as a biochemical marker for photosynthetic capacity in teak genotypes.

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