Expected genetic gain in Acacia mangium in Los Chiles, northern of Costa Rica

Abstract

An Acacia mangium Willd. progeny test conformed by 25 families from six derivate provenances was evaluated. The trial was established in San Carlos, northern from Costa Rica in year 2006, and evaluated in 2007 and in 2010. Genetic material came from breeding selections obtained by GENFORES, a tree improvement and gene conservation cooperative, in Costa Rica and Colombia. Each family was represented by 48 progenies, randomly distributed in four pairs within each of the six blocks of the trial. In 2010, DBH, survival rate, merchantable number of logs per tree, forking presence, forking height and log quality in the first four logs were evaluated. Based on these measurements, wood commercial volume per tree and hectare was estimated. Data was analyzed with SELEGEN software in order to obtain all genetic parameters from the breeding population. All traits, except survival rate, showed family mean heritability values over 0.62. Genetic gain in commercial volume per hectare was estimated as 31.24 %, when selecting as progenitors the two best individuals from the top 12 families at four-year old, which corresponds to an estimated commercial volume/ha at this age of 67.89 m3/ha, based on a growth rate of 16.97 m3/ha/year. The two Colombian provenances were significantly superior to the rest of the evaluated materials. Genetic correlations among traits showed that diameter growth rate is early expressed in this tree species, and therefore, could be used in future selections.