Genotypic stability and genetic parameters for growth and biomass traits in a water x temperature factorial experiment with Pinus sylvestris L. seedlings

Abstract

The objective of this experiment was to study genotypic stability for growth and biomass traits recorded in treatments with optimal and limiting water availability at two different temperatures and to study how the different growth environments affected genetic parameter estimates. Open-pollinated families of Scots pine (Pinus sylvestris L.) were collected in 2 seed orchards with 28 and 35 families respectively and cultivated for 1 growth period in a growth chamber. Heritability estimates were generally moderate-high (h2 = 0.3-0.8) for growth traits in individual treatments. Joint analyses of all treatments revealed significant family x temperature and family x temperature x water regime interactions. Family x water regime interaction and family effects were not significant. The results indicate low adaptation to water availability and a higher adaptation to different temperatures in the two Swedish Pinus sylvestris populations. If we assume that our results hold for a large part of the rotation the G x E interactions imply that climate change can alter the ranking of clones in a breeding program and thus decrease genetic gain. Studies of family ecovalence values showed that a minority of families (4-31%) contributed significantly to the interactions. Selection for stability could be a possible way to reduce the negative effects of G x E interaction.