6 research outputs found
A Note on Within-Tree Variation of Specific Gravity in Sweetgum (Liquidambar Styraciflua L.)
Both radial and vertical variations of specific gravity within trees for sweetgum were analyzed. Upland and bottomland sites were studied. Six different sites (three upland and three bottomland) were selected; three dominant or codominant trees per site were chosen. In general, specific gravity was found to be a highly variable property of sweetgum wood. It fluctuates with both height and year of deposition, but the patterns were not consistent either within or among trees
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Estimation of general and specific combining abilities from a diallel cross of three inbred lines of Suffolk sheep
The investigations were based on a complete diallel cross
among three inbred lines of Suffolk sheep. Line of sire effects were
assumed to be an estimate of general combining ability effects while
sire x dam interaction was assumed to be an estimate of specific
combining ability. The line of dam effects were also a measure of
general combining ability plus any maternal effects that were present.
General and specific combining ability effects were observed for
birth weight, 120-day adjusted weaning weight, and conformation
and condition scores at weaning.
The linecross individuals were generally superior to the inbred
lambs for all six traits studied on the lambs produced by the
diallel matings. Among the linecrosses, considering all six traits,
3 x 1 and 1 x 3 appeared to be the superior crosses implying that
lines 1 and 3 combined more effectively than either lines 1 and 2 or
lines 2 and 3. Significant general combining ability effects were not
observed for any of the traits studied on the lambs born from diallel
matings. Significant specific combining ability effects were observed
only for yearling wool weight. Significant line of dam effects were
observed for birth weight and yearling wool weight indicating a possibility
of maternal effects for these two traits.
The linecross ewe lambs produced by the diallel matings were
bred as yearlings and two-year-olds to a common sire to obtain two
lamb crops for evaluation of the lamb producing ability of the linecross
ewes. No straight line ewe lambs were included. Estimates
of general combining ability and reciprocal effects were obtained on
the lambs produced by these linecross ewes. Year effects were removed
before estimates of general combining ability and reciprocal
effects were obtained. Observations were made of birth weight,
120-day adjusted weaning weight, conformation and condition scores
at weaning, endocrine gland weights, detailed carcass information,
and organoleptic and cooking evaluations. The endocrine glands
weighed were right and left adrenals, pituitary, and thyroid. Carcass
characteristics observed were cold carcass weight, carcass
grade and length, fat thickness, and rib eye area as well as brisket-flank-and-shank, shoulder and neck, rack, trimmed loin, trimmed
legs, fat trim, and kidney knob percentages. A seven rib rack was
used to determine percent total loss in cooking, percent drip, tenderness, juiciness, flavor of lean, flavor of fat, and overall
score.
Significant general combining ability effects were observed
for carcass grade, fat thickness over the 12th rib, percent fat trim,
percent kidney knob, and percent trimmed legs. All other traits
exhibited a lack of either general combining ability or reciprocal
effects. Line 1 was the highest in general combining ability for
carcass grade and percent kidney knob while line 3 was the greatest
in general combining ability for fat thickness and percent fat trim,
which was considered an undesirable trait. Line 2 was the most
effective in general combining ability for percent trimmed legs.
Considering the entire study, line 1 was the most effective
combiner followed by lines 3 and 2, respectively. The 1 x 3 and
3 x 1 linecross lambs of the diallel matings appeared superior.
Linecross 1 x 3 and 3 x 1 ewes produced crossbred lambs of outstanding
quality when compared to the lambs from the other linecross ewes
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Estimation of combining abilities from a diallel cross of three inbred lines of Suffolk sheep
Published October 1967. Facts and recommendations in this publication may no longer be valid. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalo