GENETIC VARIABILITY IN PROGENIES OF Pinus caribaea var. hondurensis AT 21 YEARS OF AGE
DOI:
https://doi.org/10.4322/rif.2015.003Keywords:
genetic improvement, genetic variation, heritability, Pinus, genetic selectionAbstract
Pinus caribaea var. hondurensis is the most common species of the genus Pinus planted in tropical regions of Brazil, due its adaptation to soil and climate conditions, fast growth, good trunk form and quality of the wood. The species is mainly used for sawmill and pulp and paper industry. The aim of this study was to estimate genetic parameters for growth traits in a open-pollinated progeny test established in the Floresta Estadual de Assis, state of São Paulo. The test was implanted in May 1987, using a 4 x 5 triple lattice design with 17 treatments (16 progenies and a control), four replications and ten plants in row per plot, spaced 3 x 3 m. The total tree height ‒ ALT and the diameter at breast height ‒ DBH were measured at 21 years of age. The analysis of variance detected significant difference among progenies for tree height. The coefficients of genetic variation were 18.4% for tree height and 9.2% for DBH. The estimates of heritability coefficient for progeny means were 0.30 for height and 0.02 for DBH, higher than the estimates obtained at individual plant level and within progenies. To establish a seedling seed orchard, it is suggested to consider the trait height and a selection intensity of 6%, which corresponds to the selection of the best 32 individuals. This procedure resulted a genetic gain of 2.8% for ALT and a population effective size ( ) of 15 unrelated and not inbred individuals. The genetic correlation between traits ALT and DBH was low and not significant, suggesting small chances of indirect selection between traits
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