Tree Improvement Program Project Report 2006 / 2007

to 2000. Crosses were completed at Kalamalka breeding
arboretum (KAL) in 1996 and at the Prince George
arboretum in 1999. Sowing was done in March 2000 at
the Skimikin Nursery, and seedlings were lifted by family
and pre-designated planting design in November 2000.
Plantations in Prince George(PG), one at the Prince George
Tree Improvement Station (PGTIS), and the other one 30
km east of PG (Wansa Creek), were established in 2001.
Because we wanted to assess both male and female
effects (20 each) but could not deal with a full factorial
(400 crosses), we grouped the crosses into sets (five) in
which four females were completely crossed with four
males. All KAL crosses were completed (80 in total), but we
missed two clones at PG (78). The crosses included north
pollen on north females, south pollen on south females, and
the two reciprocals (south on north and north on south). In
setting out the field design, we used six row-tree plots and
arranged the specific male x female crosses into small subblocks.
We also arranged the S/S, N/N, S/N, N/S crosses
for the same parents in the same place in each of four rows.
Because the PG crosses were made three years after the KAL
crosses (1996), we also collected OP cones from both PG
and KAL in the year the crosses were made at PG (1999).
Each block at Wansa creek and PGTIS are exactly the
same design. Each site has five sets of identical female
x male crosses completely crossed with each other (four
females x four males for a total of 16 crosses/set or a total
of 80 crosses per site). Each of the 16 crosses also had four
parent sources (i.e., north mother x north father, south
mother x south father, and the two reciprocals) for a total
of 320 families per site. We planted 30 seedlings for each
family as six tree-row plots in each of five blocks per site.
As a result, each block had a total of 1,920 seedlings. We
also planted out six OP seedlings for each of the 20 female
parent trees per site (20 N/N and 20 S/S) for a total of 240
seedlings per site. Thus, there are a total of 2,160 seedlings
per block and a total of 10,800 seedlings per site.
In the fall of 2001, we measured both first- (2000) and
second-year heights (2001). Because the winter of 00/01
was harsher than normal, especially at the more exposed
PGTIS plantation, we also assessed winter damage.
The PGTIS and WANSA plantations completed their
seven-year growth in 2006. The stock is about one meter
tall. To determine if photoperiod differences between
Prince George and Vernon affect bud flush and growth, we
randomly selected four specific female x male crosses per
set (a total of 20 crosses per site) including the four parent
sources combination for a total of 80 crosses (80 crosses
T R E E I M P R O V E M E N T P R O G R A M
P R O J E C T R E P O R T 2 0 0 6 / 2 0 0 7
x 6 seedlings/cross or 480 seedlings per block). Bud flush
was scored categorically on each of four days. Bud flush
was defined as the date when the terminal bud on any of
the first-order lateral shoots burst its scales. The same 20
families and 80 crosses were surveyed in each of the five
blocks (2,400 seedlings) on each of the two Prince George
plantation sites (a total of 4,800 seedlings). At the end of
the growing season, we recorded height growth for all the
stock in both the WANSA and PGTIS plantations (about
20,000 seedlings).
RESULTS
F rst-year performance (2001)
Height growth
Stock was grown at (Skimikin) in 2000 and plantations
were established in the spring of 2000. Fall height
measurements were recorded for the first- and second-year
heights. Figures 51 and 52 show the mean height growth
(cm) for each of the four female x male sources. Note
standard error bars are so small (+/-0.1 cm) that they do not
show up in the figures).
Damage assessment (2001)
As we took height measurements, we assessed winter
(00/01) damage. Table 22 shows the coding and number
of seedlings for each class of damage for the combined
assessment of both the PGTIS and WANSA plantations.
Figure 53 (WANSA) and Figure 54 (PGTIS) summarize
the same data graphically. In general, seedling damage to
progeny from PG (PG x PG) was about 10 percent less
than that from progeny from Vernon (KAL x KAL), with
the damage scores for the reciprocals falling between the
two.
Seventh-year he ght and phenology
Bud burst (PGTIS Plantation)
Delayed bud flush is one of the physiological traits observed
for progeny from southern seed orchards compared to their
northern counterparts. Because a delay in bud flush could
explain differences in growth and frost hardiness, bud flush
(Julian Date) was scored for a sample of identical progeny
from each of the four parent sources (i.e., KAL x KAL, KAL
x PG, PG x KAL and PG x PG). Figures 55 and 56 show
the Julian Date for bud burst of subtending lateral shoots.
There was no difference in bud flush for progeny from
each of the four parent sources.