INTRASPECIFIC VARIATION ON EARLY GROWTH OF Neolamarckia cadamba Miq. IN PROVENANCE–PROGENY TESTS IN WEST JAVA PROVINCE, INDONESIA

Abstrak

Genetic parameters for early growth of Neolamarckia cadamba, an indigenous species with potential as a source of timber wood, were estimated in open-pollinated provenance–progeny tests conducted at two sites in West Java Province, Indonesia. The experiment was arranged in a randomized complete block design with 12 provenances, 105 families, and five replications in four-tree row plots. Total height and root collar diameter were measured at 18 months of age. Significant differences among provenances and among families within provenances were observed for height and collar diameter at all sites, except for collar diameter among provenances at the Parungpanjang site. In general, the Garut (GSJ) provenance performed better than the Kualakencana (KKP) and Nusa Kambangan (NKJ) provenances at both sites. Evaluation of variance components at the two sites showed that the provenance effects (ranging from 0.5 to 1.7%) contributed more to the total variance than family-within-provenance effects (ranging from 0.4 to 0.6%). Genetic correlations between height and collar diameter were weak to moderate. Heritability estimates were low for all traits at Limbangan, whereas they were moderate at Parungpanjang. Estimated genetic gain for height and diameter based on proportional family selection of 0.30 was 0.13 and 0.18 at Limbangan, and 0.31 and 0.16 at Parungpanjang, respectively. Continued heritability measurement is required to obtain stable values. Stable heritability combined with family selection and within-family selection will improve genetic gain.