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characteristics. The genetic yield potential of a variety is
often masked by various crop management factors, some
of which can be controlled.
For more information, please visit Alberta Agriculture’s
website, Ropin’ the Web:
www.agriculture.alberta.ca/rvt
Yield summarization methods
For cereal crops, yield data is expressed on the basis of
varying environmental productivity (Test Yield Categories
of Low, Medium, High and Very High). Experience has
shown that yield rankings can change substantially due to
growing conditions. To reflect these differences and make
the data more useful to producers, results from a test site
that produced high yield in a particular year are now
placed into the database for ‘high’ yielding environments.
That same site may contribute to the ‘low’ yielding
category in a drought year, when yields are low.
Consistent performance over all productivity
environments indicates that the variety has good yield
stability over a wide range of environments. For new
varieties where data are insufficient to provide reasonable
estimates of yield performance in each Yield Test
Category, the overall provincial yield is a first indication of
the yield potential relative to the check.
It is important to note that many of the comparisons in the
tables are not direct comparisons. Small plot agronomic
trials are expensive to grow, and new varieties are
registered every year. It is simply impractical to grow all
the varieties at the same time. Following several years of
data collection, the yield data for a particular variety will
stabilize relative to the standard check and testing will no
longer be warranted. It is for this reason that the same
standard reference check varieties are grown every year
(
e.g. AC Barrie for CWRS wheat, AC Metcalfe for
barley), and changes do not occur very often. This means
that the only direct comparison producers can be sure of is
with that of the reference check. The “number of station-
years” column provides some indication of the unbalanced
nature of the data.
To help aid in the selection process, varieties that have
yielded statistically higher (+) or lower (-) than the
standard check are indicated. If a large difference from
the check is reported but is not significant, this could
mean the yields of the new variety have varied widely
and/or there still is not enough data to prove a statistical
difference. In all cases, for the yield data to be presented,
there must be a total of at least six station-years of data
collected over two years. With additional years of testing,
the reported yield differences will become more precise.
Variety choice should not be based solely on yield in a
specific Yield Test Category. Producers are encouraged to
consider other characteristics, such as maturity, straw
strength and disease resistance when considering a new
variety. In addition, factors such as expected growth
season rainfall, soil moisture status, disease forecasts, soil
fertility and weed pressure will affect the specific Yield
Test Category in which actual yields will occur.
Maturity ratings
As is the case for yield, growing conditions have a
tremendous influence on maturity. For example, a variety
of CWRS wheat may mature in 98 days in Lethbridge, but
take 103 days in Edmonton. In addition, a two-day
difference in maturity between varieties in Lethbridge
may amount to a five-day difference in Edmonton.
To take this factor into account, maturity is now expressed
using a five-category scale: Very Early, Early, Medium,
Late and Very Late. To aid producers with this relative
scale, the average number of days to maturity for the
standard check is reported. Note that this scale is different
for each crop type. For example, an early barley variety
will mature much earlier than an early flax variety.
Plant Breeders’ Rights
The use of Plant Breeder’s Rights logo indicates a
variety is protected by law, and seed of this variety cannot
be sold without permission and royalty payment. The use
of the logo
indicates that PBR has been applied for.
Canola
The Alberta Cereal and Oilseed Advisory Committee
does not take any responsibility for accuracy or validity of
the canola performance data.
Diseases, seed treatment and
seed testing
•
Disease ratings are compiled from various data sources
in Alberta and other Prairie Provinces.
•
Treat rye and flax seed to control seedling blight, cereal
seed for smuts and fusarium, canola seed to control
flea beetle, seedling blight and the seed-borne phase of
virulent blackleg.
•
Treated seed must not be fed to livestock, poultry or
wildlife or sold for feed. Refer to labels for maximum
storage periods of treated seed.