Abstract

A breeding strategy involving inbreeding followed by crossbreeding of inbreds requires that the production of superior inbred lines must be possible, but crosses between lines should exhibit heterosis, inbreeding should not substantially delay reproduction, and early selection between lines to be effective. Age-age correlation and the effectiveness of early selection have been extensively reported for outcrossed populations of different species, but there are no reports for inbred populations. In this study, age-age correlations based on both family means and individual trees were investigated and compared in radiata pine populations with five different inbreeding levels (F = 0, 0.125, 0.25, 0.5 and 0.75). Trends in additive genetic variance, environmental variance, heritability and age-age additive genetic correlations were estimated from an outcrossed population (F = 0).For cross-sectional area at breast height, additive genetic variance increased from 3.7% at age 3 to 29.4% at age 5, remained at about 30 % up to age 10, then declined to 15.6% at age 13.The trend for heritability was similar to that for additive variance. Age-age additive correlations between early ages and at age 13 were very high in this study (> 0.76 for sectional area at age 3). Early selection for cross-sectional area at age 13 would have been most efficient if carried out between ages 5 and 9 in the outcrossed population. Higher values for age-age correlations based both on individuals and family means were obtained at the higher levels of inbreeding. This indicates that early selection would be more efficient among inbreds than among outcrosses in radiata pine.

Keywords

radiata pine; age-age correlation; inbreeding; genetic variance; heritability; early selection

Published in

Silvae Genetica
2002, Volume: 51, number: 2-3, pages: 115-122
Publisher: J D SAUERLANDERS VERLAG

UKÄ Subject classification

Forest Science


Permanent link to this page (URI)

https://res.slu.se/id/publ/118913