科研之友
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摘要
Family genetic variability of the rooting characteristics of white spruce (Picea glauca (Moench) Voss) cuttings harvested from 3-year-old stock plants was evaluated for 75 half-sib families. Growth, root system architecture, and gas exchange of the cuttings during the rooting phase (B+0) and the two subsequent growing seasons (B+1 and B+2) were evaluated. The root initiation phase (B+0) and the root development phases (B+1 and B+2) were found to be under strong genetic control. The weak correlations found between B+0 and the B+1 and B+2 phases may indicate that gene expression during B+0 is not related to root growth and development during B+1 and B+2. Strong positive correlations were observed between plant root and aboveground characteristics at the end of the B+1 and B+2 phases. This suggests that an indirect and efficient selection for white spruce families producing cuttings with heavier root dry masses could be based on the measures of aboveground morphological characteristics. Finally, the strong genetic control of morphological characteristics found in this study indicates that the selection of superior genotypes at a clonal level is possible for intensive forest management.
