Genetic variation in nutrient utilization and growth traits in Picea abies seedlings

Genetic variation in nitrogen (N) and phosphorus (P) utilization (amount of total biomass produced per unit nutrient in the needles) and growth traits in seedlings from 30 open-pollinated families of Picea abies (L.) Karst. was estimated. Seedlings were grown under two nutrient regimens: free access to nutrients and restricted access. There was a strong treatment effect on most growth traits. With free access, families allocated relatively more biomass to the stem and less to the roots than they did with restricted access. Heritabilities for growth traits were higher with free access treatment (0.33-0.81) than with restricted access treatment (0.20-0.45). Family variance components for N and P utilization were significant (p<0.05) with restricted access but not with free access. Genetic correlation between nutrient utilization and height traits with restricted access ranged from none to moderate (-0.31 to 0.56). Genetic correlations between the same trait assessed in the two treatments were strong for height and moderate for biomass.