Influences of testing sites on the genetic correlations in open-pollinated family trials of Pinus elliottii in South Africa.

Two series of open-pollinated family trials of Pinus elliottii, the so-called foreign selection series and the Zululand selection series were repeated, respectively, on four and three sites situated in sub-tropical and cooler-temperate climates of the summer rainfall and constant rainfall areas of South Africa. These series were studied in order to determine how testing sites influence the genetic correlations between traits commonly measured in progeny trials. No trend was detected between site index and genetic correlation, but site drastically changed the size and sign of the genetic correlations between growth traits and stem form. Even the genetic correlation between height and diameter at breast height was strongly affected by site.