EARLY PERFORMANCE AND GENETIC GAIN OF <em>CEDRELA</em> <em>ODORATA</em> FAMILIES FROM WIDE-RANGING SITES IN MEXICO

Abstract

Cedrela odorata is a tree of utmost importance. Thus a progeny trial was established in Veracruz, Mexico, with 168 families from 19 provenances of southeast Mexico. Significant differences among provenances and families were found at 3, 5, 7 and 11 years of age for height, diameter at breast height [dbh] and volume, and stem straightness and branch thickness at 11 years of age. Individual heritability (h²_i) fluctuated between years from 0.16 to 0.29, improving with age. For straightness and branch thickness, h²_i = 0.12 and 0.10 respectively. Growth traits showed a genetic correlation (r_g ≥ 0.99) among them. Genetic correlation (r_g) of straightness with height, dbh, volume and branch thickness were -0.24, -0.13, -0.18 and 0.56 respectively, and r_g of branch thickness with height, dbh and volume were 0.04, 0.11 and 0.13 respectively. Age-age genetic correlations were ≥ 0.93 for growth traits. A 56% gain in volume was obtained by using this variable as the selection criterion, leaving 20% of the best trees standing. Early selection at three years old, based on dbh was efficient to improve volume at 11 years with 37.3% gain, whereas at seven years the volume gain was 54%. None of the options dramatically altered form variables.