From Scott Haley and Jim Quick, 6/94 (kdk)
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About Winter Wheat Data
Scott D. Haley
Assistant Professor of Plant Science
Department of Plant Science
South Dakota State University
phone: 605-688-4453
email: haleys@mg.sdstate.edu
James S. Quick
Professor of Agronomy
Department of Agronomy
Colorado State University
phone: 303-491-6483
email: jquick@shep.agsci.colostate.edu
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These files contain data collected as part of a research project
conducted at Fort Collins, Colorado, during the 1986-1987 growing
season. The objectives of the study were to identify variability for
various traits related to drought stress tolerance and establish a
database for subsequent studies on drought-related traits. Most of the
genotypes evaluated represent hard red winter wheats from the Great
Plains. Some soft winter wheats and winter durums were also among the
germplasm evaluated.
NOTE: The data in these files is for informational purposes only. It
is not to be used as data for publication nor may it be cited
in any published documents.
The variables are divided into four separate files:
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File Name Characteristic Column Header
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table1.??? Heading HD
Anthesis AN
Physiological Maturity MAT
Grain Filling Duration DUR
table2.??? Flag Leaf Width WID
Flag Leaf Length LEN
Flag Leaf Area LA
Specific Leaf Weight SLW
table3.??? Flag leaf epicuticular EW/WT
wax content (unit dry weight)
Flag leaf epicuticular EW/LA
wax content (unit area bases)
Flag Leaf Stomatal Frequency SF
Awn Dry Weight AWN
table4.??? Grain Yield GY
Grain Volume Weight (Test Weight) TW
Kernel Weight KW
Plant Height HT
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Eighty-one genotypes (cultivars and experimental lines) were planted
on 22 September, 1986, in a 9 x 9 partially balanced lattice with four
replications. Plot size was six rows, 3.7 meters long, with an inter-
row spacing of 0.3 meters. Seeding rates were not adjusted for
differences in kernel weight among the entries (40 grams seeded per
plot). Sampling for all traits (including mechanical harvest) was
done within the central four rows of each plot. Abundant (and evenly
distributed) precipitation, coupled with sub-irrigation from a high
water table, resulted in extremely luxuriant crop growth and
development and exceptionally high average yields. No disease or
insect pressures were noted.
The following are detailed descriptions of the methods used to measure
each trait in the database:
Epicuticular Wax Content
------------------------
A gravimetric procedure (D.A. Johnson, USDA-ARS, Logan, Utah, personal
communication) was used for flag leaf epicuticular wax (EW)
quantification. Plots were sampled at post-anthesis, on 15 June 1987.
Duplicate samples of approximately 100 cm2 (estimated by prior LA
measurements) of random flag leaves were collected, placed into pre-
labeled plastic bags, and transported to the lab. Leaf areas were
determined (F87, F88) with an LI-3000 leaf area meter (LI-COR Inc.,
Lincoln, NE), except at B88 where severe leaf rolling made leaf area
measurements impossible. Samples were placed in the freezer to
preserve them until EW analysis.
For EW extraction, leaf samples were carefully placed with forceps
into clean 50 ml beakers. Samples were then washed three times in 15
ml CCl4 (carbon tetrachloride). Total wash time was 40 s for each
sample. A teflon repipette was used to dispense the CCl4. The
solvent and wax were then filtered through Watman #1 filter paper into
clean, dry, 25 x 150 mm test tubes pre-weighed to 0.1 mg with a
Mettler H34 analytical balance. After filtering, tubes were suspended
in a 75°C water bath to evaporate the solvent. A circulating fan was
positioned directly above the tubes to promote evaporation. Once
evaporation was complete, tubes were removed from the bath and placed
in a 90°C oven. After 24 h the tubes were removed and allowed to come
to room temperature. Leaf samples were placed in the oven, at 60°C
for 24 h. Cooled tubes and leaf samples were then weighed to 0.1 mg.
The wax residue was visible as a tan to yellow solid on the bottom of
the tubes.
Two blanks per set of 18 tubes (9 plots = 1 block) were also carried
through the entire process. To correct for contamination associated
with solvent, filtering, or glassware, data were corrected by
subtracting the average weight of the two blanks from the net EW
weight of each sample. The blank weight typically accounted for less
than 5% of the EW yield. EW was calculated from the average of the
two samples, reported on both a leaf area (EW/LA; reported in mg m-2)
and leaf dry weight (EW/WT; reported in g kg-1) basis.
Stomatal Frequency
------------------
Stomatal frequency (SF; reported in number mm-2) was estimated from
leaf impressions collected in the field at heading from intact flag
leaves. A thin layer of clear cellulose acetate (nail polish) was
applied to the middle region of the adaxial surface of two random flag
leaves in each plot, taking care to avoid the midrib. This was
allowed to dry roughly 5 min and removed with a small piece of clear
cellophane tape. Each impression was then applied to a piece of wax
paper or plastic transparency for storage. Impressions were examined
at 100X on an Olympus BH-2 microscope (Olympus Optical Co., LTD.,
Tokyo, Japan). Three stomatal counts were recorded per impression,
totaling six per plot. Analysis of variance was done on the average
of the six samples.
Awn Dry Weight
--------------
Four random spikes were collected from each plot near maturity and
placed in paper bags for awn dry weight measurements (AWN; reported in
mg per 20 awns). Twenty awns were clipped (at the tip of the glume)
from the central portion of each spike, placed in pollinating bags
(smooth surfaced; awns did not stick to the bags), and dried in a 60°C
oven for 48 h. Awns were then weighed to 0.1 mg on a Sartorius 1207-
MP2 analytical balance (Brinkman Instruments Inc., Westbury, NY). The
average of all four samples was used in the analysis.
Flag Leaf Area
--------------
Flag leaf area (LA; reported in cm2) was determined after heading,
following cessation of leaf expansion (Simmons, 1987), in the field on
intact flag leaves. Width (WID; reported in mm) and length (LEN;
reported in cm) of five randomly selected flag leaves were measured at
the broadest portion of the blade and from the auricle to the leaf
tip, respectively. Area was then calculated as the product of WID and
LEN, multiplied by 0.7 (determined by Fowler and Rasmusson, 1969, as
appropriate for barley leaves). The areas were averaged to obtain an
estimate of single flag leaf area.
Specific Leaf Weight
--------------------
Specific leaf weight (SLW; reported in g m-2) was determined using
leaf area and leaf dry weight measurements obtained during the EW
extraction procedure.
Maturity, Duration of Grain Filling, and Yield
----------------------------------------------
The number of days (from January 1) to mean heading (HD) and anthesis
(AN) dates were recorded. Mean physiological maturity (MAT) was
estimated as the number of days (from January 1) to the appearance of
yellow or brown glumes on 50% of the spikes in the plot. Duration of
grain filling (DUR) was calculated as the number of days between
anthesis and physiological maturity dates (Gebeyehou et al., 1982).
Grain yield (GY; reported in g m-2), grain volume weight (test weight,
TW; reported in kg m-3), and kernel weight (KW; reported in mg kernel-
1) were obtained following harvest.