| dc.description.abstract | The effects of four factors on nine attributes of black
spruce (Picea mariana (Mill) B. S. P.) seedlings were
investigated. The seedlings were produced under an
accelerated transplant system that used a 6 ml Castle and
Cooke container. The experiment had two stages. The first
stage investigated the effects of the duration of the
greenhouse phase (DURATION), outplanting date (OUTPLANTING
DATE) and acclimatization of seedlings to outdoor
environmental conditions before transplanting
(ACCLIMATIZATION) on seedling attributes at the end of the
greenhouse phase. The seedling attributes were height and
the number of roots outside the growing medium. The second
stage investigated the effects of these same factors plus
shade in the transplant beds (SHADE) on seedling attributes
during, and at the end of, the first growing season.
Seedling mortality in the transplant beds and bud-set were
monitored during the growing season. Total height, top dry
weight, root dry weight, bud diameter, and root collar
diameter were measured at the end of the growing season.
Analysis of variance was used to investigate the effects of
the factors on the response variables. The major conclusions
were these. The greenhouse cultural factors studied affected
both the morphological state of the seedling and its
physiological fitness at the time of transplanting. DURATION
was especially influential in this regard. At 7 weeks the
seedlings were small and experienced high mortality if
transplanted. By 10 weeks the seedlings were larger and survived the transplanting operation well, but they were
predisposed to set bud soon after transplanting.
Thirteen-week-old seedlings were even larger, and were
beginning to outgrow their containers. They survived
transplanting well, but were even more predisposed to set
bud. DURATION effects also influenced the morphological
state of the transplants at the end of the first growing
season. Seedlings that set bud early had short, stocky stems
with large buds and a high root:top ratio. Seedlings that
did not set bud early had tall slender stems with small buds
and a low root:top ratio. OUTPLANTING DATE, SHADE and
ACCLIMATIZATION also affected the crop and interacted with
DURATION and one another. The results provide insight into the first year response of seedling grown under the Castle
and Cooke accelerated transplant system to cultural factors
over which nurserymen have control. | |
