b'are expensive to grow and new varieties are registered everyand that growth environment has a tremendous influence on year. Its simply impractical to grow all varieties at the same time.maturity dates. Hot, dry conditions will compress the reported Following several years of data collection, the yield performancematurity differences just as cool, wet conditions will expand for a particular variety stabilizes relative to the check and furtherthem. For example, a variety of CWRS wheat may mature in 98 testing is no longer required. Its for these reasons the checkdays in Lethbridge but take 103 days in Edmonton. Likewise, a varieties are grown every year (ex: Carberry for CWRS wheat, ACvariety which is on average two days later maturing across the Metcalfe for barley) and changes to these checks are infrequent.province may be only one day later in southern Alberta but The Overall Station Years of Testing column provides ancould be three or more days later in a northern location.indication of the unbalanced nature of the dataset. At least six site-years of yield data collected over two yearsFalling Number and Resistance to Pre-harvest are required prior to reporting the figures in this publication.SproutingFor new varieties, Overall Yield is often the first indicationFalling number is a measurement of the extent to which of yield potential relative to the check. As additional dataendosperm starch in the seed has been metabolized to simple becomes available, yield performance is also expressed onsugars during the germination process. There are many the basis of environmental productivity (Yield Test Categoriesinter-related genetic, environmental and management factors of Low, Medium, High, and Very High). Where there are lesswhich influence seed germination prior to harvest. In general, than six site-years of data for a yield column, an indication willconditions in which the crop is harvested soon after maturity be made that there is insufficient data to describe, symbolizedprior to inclement weather will result in the retention of high by reporting an XX. Yield rankings among varieties canfalling number. Thus, the use of earlier maturing varieties with change substantially due to growing conditions. To reflect theseGood or Very Good pre-harvest sprouting resistance in short-differences, results from a test site which produced high yield inseason areas is usually an effective management decision for a particular year are placed into the database for high yieldingmaintaining high quality. A rating for pre-harvest sprouting environments. The same site may contribute to the low yieldresistance is provided for most of the reported wheat varieties category in a drought year when yields are low. Consistentbased on controlled environment conditions. These ratings performance over all Yield Test Categories indicates a varietyreflect genetic differences. Varieties with Good or Very Good has environmental responses similar to the check and maypre-sprouting resistance will normally retain their falling number have good yield stability over a wide range of environments.for longer periods of time under cool, wet harvest conditions. Scientific studies conducted on variety performance in WesternHowever, even these varieties will initiate germination when Canada have shown that Yield Test Category analysis providesmature and exposed to prolonged conditions favourable to a more reliable indication of yield performance than resultssprouting, resulting in falling number reductions. Note that organized by geographic region. falling number can be reduced without visible signs of sprouting.The yield comparison tables have several features:Overall actual yield of the check (bushels per acre) based onSeed Size and Plant Populationsall data available to the testing program is provided alongSeed size within a crop kind will vary from variety to variety, with the number of station years of testing.requiring adjustment of seeding volumes to achieve desiredThe range in yield for each Yield Test Category is defined. plant populations. Some of the tables provide an average 1000Actual yield of the check in each Yield Test Category iskernel weight (TKW) which can be used as a guide for variety reported. differences. The best approach is to determine the 1000 kernelF or varieties with sufficient data, the Overall Yield andweight of the seed to be planted, germination rate, emergence performance in each Yield Test Category is expressedmortality, and in the case of fall seeded crops, an estimate of relative to the check. winterkill. For more information and user-friendly seeding To make effective use of the yield comparison tables,rate calculators which take into account these and other producers should set a realistic yield target for the season andconsiderations, please see www.agric.gov.ab.ca/app21/ldcalc. determine where it fits within the Low, Medium, High and (in some cases) Very High Yield Test Categories. This approachPlant Breeders Rightsfacilitates matching of variety choice to expected productivityPlant Breeders Rights (PBR) are a form of intellectual property levels and is similar to that used when making decisionsrights by which plant breeders can protect new varieties in the on other levels of inputs. Please note the actual yield levelssame way an inventor protects a new invention with a patent. In indicated are from small plot trials, which may be 15 to 202015, Canada amended the PBR Act to bring it into conformity per cent higher than yields expected under commercial fieldwith UPOV91. Varieties protected under the previous legislation production.(UPOV78) are indicated with the logo, whereas those protected under the new UPOV91 legislation that are shown Maturity Ratings with the new logo. For more information on Plant Breeders Based on feedback from producers, the six-category scale forRights, please see www.pbrfacts.ca or the Canadian Food maturity (Very Early, Early, Medium, Late, Very Late, ExtremelyInspection Agency website at www.inspection.gc.ca.Late) has been replaced with average differences in days, relative to the check. Be aware these are averages from severalVariety Use Agreement years over the vast agricultural production area of AlbertaA few new varieties are participating in a Variety Use Agreement Spring 2021 71'