To obtain a better understanding of the pattern of adaptive variation of Piceamariana (Mill.) B.S.P. from northwestern Ontario, a short-term provenance test was carried out for 75 seed sources collected east and west of Lake Nipigon. Provenances were grown in common environments at a greenhouse for two seasons (1990–1991) and a farm field and a forestry trial each for four growing seasons (1990–1993). Twenty-five growth and phenological variables were determined, including seedling height, needle flushing date, and the timing of shoot elongation. Significant levels of interprovenance variation were present for 18 of these variables. Graphic analysis of the pattern of variation indicated that sources from the southwestern portion of the collected area generally grew faster and flushed later than easterly sources near the north shore of Lake Superior. Superimposed on this general pattern were several irregularities caused by one or more provenances. Multiple regressions were run for each of the 18 variables against latitude, elevation, and 12 climatic variables interpolated for each of the seed sources by a geographic information system from 1951–1980 data obtained from 56 nearby weather stations. Large coefficients of variation (up to 0.57) were obtained for some variables. Combinations of climatic variables, including winter minimum and summer maximum temperatures together with precipitation and timing of the growing season, were excellent predictors of black spruce needle flushing dates, while summer temperature, precipitation, and elevation were moderately good predictors of height growth.
Genetic parameters of growth traits were estimated for first-generation selections of black spruce ( Picea mariana (Mill.) BSP) in northwestern Ontario from 720 open-pollinated families and more than 42 000 trees. Unbiased estimates of narrow-sense heritability for tree height growth averaged 0.19, 0.18, and 0.14 at ages 6, 11, and 19 years, respectively, from combined-site analyses compared with 0.25, 0.23, and 0.16 for the same ages from single-site analyses. Heritability estimates for diameter at breast height and stem volume were lower than that of height at age 19, suggesting that tree height is a more desirable trait for selection in black spruce. The moderately high estimates of type B genetic correlations implied limited operational importance of genotype × environment interactions. Estimates of age–age genetic correlation were high (>0.88) among cumulative tree height growth at 6, 11, and 19 years but lower between height increments from different age intervals. Estimates of type B age–age genetic correlation were more than 0.2 lower than their type A counterparts, suggesting strong effects of common environments on the estimates of type A genetic correlations. Based on the relative selection efficiencies, selection on cumulative tree height between ages 6 and 11 was more efficient than at age 19.
A factorial experiment was used to evaluate light, a range of alternating temperatures, and stratification on germination of freshly collected current year's seed of Piceamariana (Mill.) B.S.P. Light was required for complete germination of unstratified seed at low (5–15 °C) and moderate (10–20 °C) temperatures. This light requirement was removed by moist chilling at 3 °C for 24 days.
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