Variety selection is critical to profitability because in South Carolina we are highly dependent on varietal resistance for disease and insect management. No variety is perfect, but the ideal variety would have: consistently high yield potential, high test weight, Hessian fly resistance, powdery mildew and leaf rust resistance, and straw strength. Moderate height is also desirable (except for straw production) to reduce lodging risk and residue for double-cropping.
AGS 2031 is a beardless, short-med. height wheat with medium maturity, high yield, and high test weight. It is probably best adapted to the southern coastal plain. In Georgia tests AGS 2031 had the highest 3-yr yield average. AGS 2031 is fly susceptible but has resistance to mildew, leaf rust, stripe rust, and soilborne mosaic virus.
AGS 2026 is medium maturity and height, with resistance to leaf rust, mildew, and race L Hessian fly. It has never been entered in the wheat challenge test so we have not compared its yield potential. Seed supply is very limited.
Coker 9700 is a beardless, medium height, medium maturity wheat with high test weight. It is susceptible to Hessian fly and leaf rust.
Pioneer 2687 is a bearded wheat with medium height. It has no Hessian fly resistance but good leaf rust resistance. At Blackville in 2008, it had excellent test weight, but yield was 11 bu below test average.
S. States 8641 is a beardless, medium maturity wheat. It is medium/tall, about the same height as AGS 2000.
SS 8641 has resistance to Hessian fly, leaf rust, stripe rust, mildew, and soil-borne mosaic.
Vigoro Oglethorpe is beardless with medium height and some resistance to race-L Hessian fly. It has good rust resistance, but is susceptible to powdery mildew. It did not lodge at Blackville, but is rated ashaving fair straw strength in Georgia tests. Seed is very limited in 2008.
Unless only a small acreage is involved, it is always a good idea to plant more than one variety to spread risk. Try 2 - 3 of the top varieties for your area depending on your acreage. Variations in pest severity and weather conditions will favor one variety over another in any given year. When trying a new variety for the first time, you should usually keep the majority of your acreage in a proven performer.
Use of certified seed provides a level of insurance against poor germination, seedborne diseases, and weeds. Since we are dependent on the continued development and release of specialized varieties adapted to our climate and pest complex, it benefits everyone to obey all seed laws.
Maturity: Maturity can be defined in different ways, and depending on the growing season, a medium maturity variety might be ready to harvest within two - three days of an early variety planted on the same date. The most important consideration is that early varieties will joint and head earlier. Therefore, early varieties are more susceptible to stem freeze in March and head freeze in April if planted too early.
Hessian Fly Resistance: Varietal resistance has worked well in controlling Hessian fly in S. C., but Hessian fly is a moving target. A “poor” rating indicates susceptibility throughout the state; “fair” indicates some resistance which may be inadequate under heavy pressure; “good” indicates resistance to the predominant fly races in the southern coastal plain (roughly below Lake Marion); Good +L indicates some resistance to race “L” Hessian fly found in the northern Coastal Plain (above Lake Marion). If a previously resistant variety fails on your farm you will need to protect it with insecticide or change varieties in the future.
Disease Resistance: Rust and mildew resistance can change even more rapidly than insect resistance, and disease ratings are always relative. The ratings used in the table are based on our latest observations at Blackville, when available, and neighboring states. Even varieties given only a “fair”rating exhibit a significant level of resistance when compared with highly susceptible varieties.
Test Weight & Test Weight Index: Test weight ratings are based on performance over a period of years, but this is one characteristic that is very stable. That is, test weights may vary greatly depending on field conditions, but high test weight varieties maintain consistently better test weights over many years. The test weight index shows the percent above or below average test weight in a series of trials. The superscript number shows how many years the variety was evaluated. For example, a TW index of 2.83 means that over a 3-year period the variety’s test weight was 2.8 % above the average of other varieties tested. This would be exceptional out-performance.
Yield Index: The yield index indicates the percent above or below test average yield and the superscript shows the number of years compared. Consistent yielders have a positive index over several years. A high number based on only one year’s information is less meaningful.
Height: A value over 41” (105 cm) is a tall wheat for our area and under 35” (90 cm) is relatively short. These heights are taken under high yield conditions. Keep in mind that some tall varieties have excellent straw strength and standability.
Straw Strength: Is based on lodging comparisons at N rates of 90 - 120 lbs / ac.