ESTIMATES OF GENETIC-PARAMETERS AND CORRELATIONS OF JUVENILE CHARACTERS BASED ON OPEN-POLLINATED PROGENIES OF HEVEA

An investigation of 10 characters was conducted in three-year old open pollinated progenies of rubber tree [Hevea brasiliensis (Willd. ex Ad r. de Juss.) Muell. Arg.]. The experiment included 17 families replica ted in five blocks of ten tree rows. The characters studied were: aver age yield according to Hamaker-Morris-Mann test, virgin bark thickness , total number of latex vessel rings, overall density of latex vessels per ring per five square millimeters of bark, average diameter of lat ex vessels, average distance between consecutive latex vessel rings, a verage leaf area, crown form and stem circumference. Heritability as w ell as genotypic, phenotypic and environmental correlations among char acters were estimated. Heritability values from progeny analysis data ranked from 0.08 (average distance between consecutive latex vessel ri ngs) to 0.82 (average yield). Positive genetic correlations were found between average yield and characters of the laticiferous system. No r elationship was found between average yield and stem circumference. Cr own form and average yield were related (r = 0.55493), indicating that trees with high yield tend to have better crown form. No phenotypic c orrelation was found between average yield and total number of latex v essel rings, average leaf area, average diameter of latex vessels and average distance between consecutive latex vessel rings.