• Sulzer, Andrea M.
  The Graduate School, University of Maine
  

A retrospective test of 36 half-sib black spruce (Picea mariana [Mill] B.S.P.) families was initiated in 1988 using surplus seed from the same families growing in six ten-year-old test plantations in New Brunswick. Gas exchange rates, cold hardiness, chlorophyll content, leaf weight/leaf area ratios, height and diameter of the three-year-old seedling were terminated. Seedling measurements were related to field height at age ten. The variables that correlated most highly with height at age ten were seedling height and diameter. Seedling cold hardiness was significantly correlated with both three-year and ten-year height, the better growing families being more cold hardy. Although photosynthesis and the ratio of photosynthesis to transpiration (a measure of "instantaneous" water use efficiency) were correlated with seedling height, neither of these measures showed a significant relationship with height at age ten.

The most accurate classification of family field performance (as either superior, average, or poor, according to ten-year height) was achieved with seedling diameter and height, respectively. Classification was somewhat improved when the variable chlorophyll content was combined with either of these growth measures. Cold hardiness, in combination with seedling height (but not diameter) also improved classification, but only of poor families. Further trials are required to validate these results and to determine the usefulness of physiological and morphological parameters for early testing purposes.