Genetic variation in growth, carbon isotope discrimination, and foliar N concentration in Picea mariana: analyses from a half-diallel mating design using field-grown trees

Abstract

The authors performed genetic analyses of growth, carbon isotope discrimination (?¹³C), and foliar N concentration using a half-diallel subset of a 7 × 7 complete diallel planted on three sites ranging in water availability. Trees were 22 years old. Heritabilities; general and specific combining abilities; as well as phenotypic, genetic, and environmental correlations were calculated using the best linear unbiased prediction and restricted maximum-likelihood methods. The four traits measured showed variable levels of genetic control. The calculated heritablilities for the traits were as follows: height, 0.39 ± 0.22 (estimate ± SD); diameter, 0.14 ± 0.10; ?¹³C value, 0.54 ± 0.26; and foliar N, 0.00. Phenotypic correlations were moderate (r = -0.35), genetic correlations were strong (r = -0.97), and environmental correlations were weak (r = -0.18) between height growth and ?¹³C. The strong negative genetic correlation between ?¹³C and growth supports earlier work with a subset of families indicating photosynthetic differences caused genetic variation in ?¹³C. Inbreeding greatly decreased growth while not impacting ?¹³C. High heritability, lack of inbreeding depression, and low environmental correlations indicate that a major proportion of ?¹³C genetic control may be relatively simple. Because ?¹³C is highly heritable, highly genetically correlated to growth, less environmentally sensitive than growth, and has the possibility of early selection, the trait is a good candidate trait for indirect selection for growth.

Citation

Johnsen, Kurt H.; Flanagan, Lawrence B.; Huber, Dudley A.; Major, John E. 1999. Genetic variation in growth, carbon isotope discrimination, and foliar N concentration in Picea mariana: analyses from a half-diallel mating design using field-grown trees. Can. J. For. Res. 29: 1727-1735