GENETIC CONTROL OF GROWTH RATE AND WOOD TRAITS IN Pinus patula

Abstract

In order to evaluate the expected response to selection for several economically important traits, the genetic variation and heritability of growth traits, wood specific gravity, and latewood proportion were estimated in a progeny test with six-year-old 22 half-sib families of Pinus patula Schl. et Cham., established at Zacualpan, Ver. Wood specific gravity showed the highest heritability values both at the individual and family levels (h2 i =0.25 and h2 F =0.64), compared to the other traits (h2 i £0.15 y h2 F £0.55). However, wood specific gravity showed much lower values of additive and phenotypic variation than the other traits, so its response to selection would be less than that for growth rate. Similarly, assuming the same selection intensity, individual selection would be more effective than family selection.