Variation in nutrient utilization and juvenile growth in open-pollinated families of Picea sitchensis (Bong.) Carr. grown in a phytotron and correlations with field performance

摘要

The purpose of this study was to estimate genetic variation in nitrogen (N) and phosphorus (P) utilization (= amount of biomass produced per,unit nutrient in the needles), and growth traits in seedlings from 27 open-pollinated families of P. sitchensis. Further, the purpose was to estimate juvenile mature correlations between these traits and breast height diameter in field trials. The seedlings were grown for two growth periods in climate chambers. There were two treatments: free access and restricted access to nutrients. The nutrient treatment in. restricted access was chosen to result in a growth of approximately one third of the growth in the free access treatment. Height, shoot, root and needle dry weights, as well as amount of N and P in the needles and N and P utilization were assessed. There was a strong treatment effect of nutrients on all height and above-ground biomass traits. They were statistically different at the 1 % level. There was a significant family effect for N and P utilization and for all other traits studied under restricted access to nutrients. On the contrary, no significant family effects were noted for nitrogen and phosphorus utilization under free access to nutrients, this may be attributed to luxury consumption of nutrients. The precision of the family variance estimates and heritabilities were slightly higher in restricted access than in the free access treatment. The family x nutrient interaction was significant for most of the traits studied, which resulted in non-significance for most of the family effects in the joint analyses of data from the two treatments. Selection of families that responded strongly to a high availability of nutrients could be useful at regeneration of sites with high soil fertilities. The family mean correlations between juvenile traits and breast height diameter in field were all weak (R-2 less than or equal to 0.2).