Performance trials of 82 released wheat varieties and experimental lines were conducted cooperatively by the Virginia Tech Small Grain Variety Testing and Small Grain Breeding programs at seven locations throughout Virginia in the 2005-06 growing season. Testing locations are shown in Figure 1. Preliminary data from the trials is available at the Grain Crops Management website: www.grains.cses.vt.edu/grains.
Figure 1. Testing locations in Virginia.
Performance of varieties in relation to economically important traits, such grain yield, test weight, maturity, plant height, disease resistance, and milling and baking quality vary over environments including years and locations. Additional variation in a given experiment for yield and other traits results from test site and plot location in the field and other non-controllable biotic and abiotic factors. Replicated tests are conducted to account for this variation and statistics are reported in the data tables to assist the reader in making valid comparisons between varieties. The magnitude of difference between two varieties for a given trait which may have resulted from uncontrollable variation is computed for the data and is listed at the bottom of each data column as the LSD (.05) (least significant difference with 95% confidence). Differences between two varieties that are less than the LSD value are assumed to be non-significant at a 95% confidence level.
When making variety selections it is important to realize that wheat varieties differ in their performance in different environments. Some varieties are more adapted to a wide range of environments. Performance may vary with year and location variations in rainfall, temperature, pests and other environmental variables. In these experiments, many varieties have essentially the same yield, and great care should be taken in interpreting and applying the results from a single year's tests, especially at only one location. For these reasons it is important, whenever possible, to also look at the average performance of a variety across locations when making variety selections. Multi-year averages give even greater confidence to variety performance decisions. The over location and multi-year tables compare the yield of a variety across multiple environments and years. These tables are an excellent summary of yield potential comparisons among varieties.
Selecting the best wheat varieties is challenging but becomes easier with adequate information on performance over multiple environments. Past seasons across Virginia have provided the opportunity to evaluate daylength sensitivity, spring freeze damage, and resistance to diseases such as glume blotch, scab (Fusarium head blight), and stripe rust as well as general plant health. Many newer wheat varieties and lines performed well in all environments tested.
Producers who grow large acreages of wheat should plant two or more varieties having significantly different maturity dates in order to ensure harvest of high quality grain having high test weight and no sprouting. In Virginia it is typical that the first good week of wheat harvest is followed by a period of sporadic or consistent rain showers, which delay subsequent harvest and significantly reduce grain test weight and quality. Growers can circumvent this problem by planting varieties that differ significantly in maturity wherein early maturing varieties often can be harvest first and prior to significant rain showers, and later maturing varieties harvested subsequently will suffer less damage and losses in test weight and quality due to exposure to such a rain event.
The released varieties that yielded significantly higher than the statewide mean in 2006 were Southern States 550, Pioneer Brand 26R24, Pioneer Brand 26R15, Southern States MPV 57, Vigoro 9510, USG 3209, Sisson, Southern States 560, and Chesapeake. Sisson and Chesapeake also had mean test weights that were significantly higher than the test average. The fact that varieties with a wide range in maturity and other characteristics did well this year is promising in that producers have the opportunity to select good varieties to fit different management schemes. Test weights overall were high due to favorable environmental conditions during grain fill.
Varieties with three year average yields higher than the statewide average include Southern States MPV 57, USG 3209, Pioneer Brand 26R24, Southern States 550, Southern States 560, Featherstone 176, and Pioneer Brand 26R15. In addition to yield potential, maturity, plant height and disease resistance, producers should select varieties on the basis of intended markets and end use quality.
Other varieties with above average yields across two years are Southern States 8404, Vigoro 9510, USG 3706 and Sisson.
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