Virginia wheat growers have seen a rapid development of new mildew races. In two of the most popular varieties, McCormick and Tribute mildew resistance is breaking down rapidly.
Despite powdery mildew problems, Tribute continues to have the highest test weights in Virginia’s statewide testing program and has averaged about 90 bushels per acre yields. Likewise, McCormick still has the production advantages that made it one of the top varieties grown over the past few years.
However, growers currently growing these varieties have had to increase sprays to manage the disease. The cost of spraying in many cases exceeds the production advantages of these staple varieties and will likely force growers to look for replacement varieties for the 2009-2010 growing season.
Fortunately, growers in Virginia and North Carolina will have several good wheat variety options. A number of high quality wheat varieties have been developed through the breeding program of Virginia Tech Professor Carl Griffey. Griffey’s research team also screens thousands of potential varieties from other states.
Griffey recently reviewed a number of wheat varietal options during a Virginia Grain Growers Association Field Day in Water View, Va.
Renwood 3434 is a good, short variety for double-cropping with soybeans, Griffey says. This variety has the three-year yield average of 89 bushels per acre, with 92 bushels per acre last year. It has an average test weight and is still showing good resistance to powdery mildew.
USG 3665 is a medium to full-season variety. It was the top yielding variety in statewide tests last year. And, it remains one of the top yielding varieties over the three-year test period. It is a tall-growing variety, with good powdery mildew resistance and leaf rust resistance.
USG 3555 is a replacement for USG 3209. It has better straw strength and better resistance to leaf and stripe rust. It still shows good resistance to powdery mildew. At 96 bushels per acre, it was among the top yielding varieties last year and averaged over 92 bushels per acre in three-year testing.
Bransom at 95 bushels per acre last year and nearly 92 bushels per acre over the past three years is another good choice, Griffey says. It is a medium full-season variety with good to moderate resistance to powdery mildew and leaf rust.
Coker 9804 is a new variety out of the Coker program. It is an early heading variety with good yields (85 bushels per acre). It has good resistance to powdery mildew, but only moderate resistance to leaf rust.
Shirley is a new wheat variety that should be available to growers for fall 2009 planting. It has consistently produced high yields, with over 93 bushels per acre over the past three years and 97 bushels per acre last year. It is a full-season variety, with very good resistance to powdery mildew and leaf rust.
Dominion is another varietal option, with good, but not great yield averages over the past three years. It has one of the same mildew genes as McCormick and Tribute, but has other resistance genes that give it moderate to good powdery mildew and leaf rust.
Vigoro 9510 has consistently produced 88-90 bushels per acre with good test weights, but has only moderate resistance to powdery mildew and leaf rust. Both Vigoro 9510 and Dominion are susceptible to wheat spindle streak, which has caused problems for Virginia wheat growers late in the 2009 season.
Pioneer 26R22 has been a top seller in North Carolina and is being introduced into Virginia for the 2009-2010 season. It is susceptible to Hessian fly, but highly resistant to striped rust.
Pioneer 26R15 has been one of the most consistent wheat varieties in Virginia over the past few years with yields consistently in the low 90-bushel per acre range. It is a full-season variety, with good resistance to powdery mildew and leaf rust.
Jamestown and Southern States 520 are two of the earliest heading varieties in the Virginia test. Jamestown is the earliest, but with yields typically in the mid-80 bushels per acre range. It has consistently good test weights (in the low 60s) and still has good powdery mildew resistance. Jamestown also has good Hessian fly resistance.
Sisson is another early heading variety that has been around a few years. It has shown break down of mildew resistance. It has slightly higher yield potential than Jamestown and also has good test weights. It is highly susceptible to leaf rust, and growers planting this variety may have to spray it for rust, according to Griffey.
Griffey noted that early-maturing varieties have lower yields, typically, than more full-season wheat varieties. However, he points out that getting these earlier maturing fields out of the field and planting soybeans behind them early may more than make up in increased soybean yields any yields lost on the wheat.
For farmers growing wheat for a mill Southern States 5205 is a good choice because of its excellent milling and baking qualities. It is a medium-maturing variety with moderate resistance to powdery mildew and good resistance to leaf rust. SS 5205 has consistently produced 90-plus bushels per acre.
A sister variety to 5205 is Southern States 8641, which is a full-season variety with excellent yields in the Virginia tests — consistently over 90 bushels per acre.
Griffey concludes wheat growers should compare statewide wheat variety test results with local test results and then make the best decision as to which variety works best in their particular operation. Keeping the status quo may not be such a good idea because some of these older, more popular varieties are losing resistance quickly to some of the most severe yield-robbing diseases.
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