| dc.description.abstract | Genetic and environmental variance in cone and seed
properties and early progeny growth of Picea mariana (Mill.)
B.S.P. clones were evaluated using cones and seed from two to
three ramets of 19 clones each growing in a northern Ontario
grafted clonal seed orchard. A cone analysis and a germination
test were conducted to estimate variation among clones and among
ramets within clones. Variation in growth of 19 open-pollinated
families growing under two fertilizer regimes in a greenhouse was
evaluated after three, four and five months of test
establishment. Mean cone volume and mean cone length were found
to be 2.2 cm[superscript 3] and 24.4 mm, respectively. The mean for
number of seed per cone was 71, although only 18% of these seeds
were filled. Nested analyses of variance indicated that clones
accounted for 23% to 39% of the total variation in cone size and
seed yield per cone. Variation among ramets within clones for
these characteristics accounted for 13% to 19% of total variance.
The average germination percent, based on filled seed, was 68%
and was completed (90%) after 11 days. Genetic variance in
germination percent and germination speed acccounted for 67% and
21% of the total variance, respectively. For germination percent
and germination speed, 18% and 33% of the total variation,
respectively, were due to ramets within clones. In the progeny
test, family heights were highly significant at all three ages.
At five months family height means ranged from 30 cm to 34 cm and from 11 cm to 14 cm at the low and high fertilizer level,
respectively, Ramet-within-clone effects were only significant
after three and four months, when seedling heights were
significantly correlated with seed weights. Family-fertilizer
interactions were not significant at all three ages, although the
variance component for this source of variation increased
substantially towards the end of the test period. | |
