ITEMS FROM THE UNITED STATES

VIRGINIA

VIRGINIA POLYTECHNIC INSTITUTE AND STATE UNIVERSITY

Department of Crop and Soil Environmental Sciences 1 and Department of Plant Pathology, Physiology and Weed Science 2; Blacksburg, VA 240610404, USA.

J.J. Paling, C.A. Griffey, W.E. Thomason, J. Chen, J.A. Wilson, D. Nabati, T.H. Pridgen, E.G. Rucker, D.E. Brann, and M.M. Alley.

2003 Wheat Production in the Commonwealth of Virginia. [p. 269-270]

J.J. Paling, C.A. Griffey, W.E. Thomason, D.E. Brann, and M.M. Alley.

Growing conditions. Producers began planting into dry soil during autumn 2002 hoping for some moisture later, but the dry conditions that prevailed during most of 2002 changed mid way through the planting season. Autumn rains turned the dry conditions into extremely wet conditions and delayed some wheat planting until much later than usual with only 76 % of the crop planted by 16 November. These unusually wet conditions continued through the winter, and temperatures were lower than average for much of the state. Cool and wet conditions continued through April and May. Many farmers proclaimed the spring of 2003 as 'the wettest spring I can remember' and, indeed, it was one of the wettest years on record. These cool wet conditions remained through harvest season, delaying wheat maturity and harvest by 1 to 2 weeks.

Disease incidence and severity. Powdery mildew incidence was lower and occurred later than usual in the Eastern Shore and Coastal Plain regions. Above average rainfall and colder than average temperatures, during the time when powdery mildew epidemics usually occur, likely delayed onset and spread of this disease. Leaf rust incidence was lower in 2003 than in 2002 over most of the state. Trace amounts of stripe rust were observed on the Eastern Shore in 2003. Lodging was most severe in areas having heavy disease during the wet spring. Reports of diseased wheat fields lodging from the wet conditions began as early as mid May. Diseases of major significance in 2003 were scab and glume blotch, which thrived under the wet conditions that occurred during heading and grain fill. These two diseases resulted in significant losses in grain yield and quality, and most grain was unsuitable for milling purposes. The 2003 season highlighted the importance of integrated pest management including planting disease resistant cultivars, treating seed, and using IPM control measures.

Insects. The cereal leaf beetle was the most prevalent insect reported in 2003. Scouting reports of insect incidence and severity were accompanied by recommendations for control. The beetle reached economic threshold and control was necessary in several fields in eastern Virginia.

State cultivar tests. During the past two seasons, the environment in Virginia has facilitated the evaluation of daylength sensitivity, spring freeze damage, resistance to glume blotch, FHB, and overall plant health in both a dry (2002) and an excessively wet years (2003). Newer wheat cultivars and lines performed well in both of these test environments. A total of 71 entries were evaluated at five locations across the Commonwealth in 2003. Included in this total were 41 experimental lines (32 developed at Virginia Tech) and 30 released cultivars. Average grain yields ranged from 42 to 77 bu/acre (2,822-5,174 kg/ha) with an overall test average of 63 bu/acre (4,233 kg/ha). Wheat cultivars with yields significantly above the test average included SS 520, Tribute, SS 550, Sisson, McCormick, Renwood 3706, SS 560, and 16 experimental lines (12 from the Virginia Tech program, including two soft white entries). Yields among genotypes in this group ranged from 66 to 77 bu/acre (4,434-5,174 kg/ha). Tests conducted in the Coastal Plain Region had a yield average of 64 bu/acre (4,300 kg/ha), whereas tests conducted in the Piedmont and Blue Ridge Region had a yield average of 62 bu/acre (4,166 kg/ha). Test weights of wheat lines (based on five locations across the state) ranged from 49.6 lb/bu (638 kg/m^3^) to 57.6 lb/bu (741 kg/m^3^) with a test average of 54.4 lb/bu (700 kg/m^3^). Of the 24 entries with test weights significantly higher than the test average, 11 were released cultivars and 13 were experimental lines. Five cultivars, McCormick, Renwood 3706, Sisson, SS 520 and Tribute, and six Virginia experimental lines, had both grain yields and test weights that were significantly higher than the test average.

Virginia no-till test. To evaluate cultivar by tillage effects, wheat was planted into corn stubble at the Eastern Virginia AREC near Warsaw, VA, on 23 October. Grain yields averaged 85 bu/acre (5,711 kg/ha) with an average test weight of 57 lb/bu (733 kg/m3). The top yielding cultivars produced more than 90 bu/acre (6,047 kg/ha) in 2003. Cultivars with moderate resistance to FHB were among the highest yielding during the past 3 years and included two new releases, McCormick and Tribute, each yielding significantly higher than the test average in all 3 years. Improved scab resistance will increase the productivity of growing wheat especially in no-till management regimes following corn.

Virginia wheat yield contests. Seven official entries were in the 2003 wheat yield contests and three additional entries were submitted for informational purposes. Three of the entries were grown in no-till and the other four entries in conventional-till regimes. In general, yields for the entries in 2003 were lower than in 2002, likely due to the wet conditions that occurred throughout much of the growing and harvesting seasons. The highest yield in no-till was obtained by George Floyd III of Northampton County. He produced 97 bu/acre (6,517 kg/ha) of Century II wheat after soybeans. George Alvis and George, Randy, and Dennis Alvis (Alvis Farms) of Hanover County had the other two no-till entries. Each of these fields of SS 520 yielded 77 bu/acre (5,174 kg/ha) after corn. Richard T. Sanford of Westmoreland County had the highest yield under conventional tillage. His field of SS 550 produced 80 bu/acre (5,375 kg/ha) grown after a previous crop of barley/soybeans. Joseph Reamey of Montross in Westmoreland County submitted two entries, one field of Sisson and a field of Vigoro 9110. Each field was grown after corn and produced 53 bu/acre (3,561 kg/ha). Jamie Lee of Prince George County was the only rookie entered in 2003. Jamie's conventional-till field of Coker 9704 yielded 71 bu/acre (4,770 kg/ha) after corn. One no-till and two conventional-till fields were included as entries for informational purposes only and not eligible for competition. David Hula of Charles City County produced a no-till field of Renwood 3260 that yielded 82 bu/acre (5510 kg/ha) after corn. The two conventional fields were grown by Richard Sanford of Westmoreland County. Both fields were grown after a crop of barley/soybeans. The cultivars Pioneer 2643 and Pioneer 2684, respectively, yielded 84 bu/acre (5,644 kg/ha) and 70 bu/acre (4,703 kg/ha).

Success of alternative breeding methods in transferring Fusarium head blight resistance to soft red winter wheat. [p. 270-272]

J. A. Wilson, C. A. Griffey, J. Chen, D. Nabati, and T. Pridgen.

Objective. Accelerate development of FHB-resistant SRWW cultivars using breeding methods other than traditional topcrossing.

Introduction. The Mid-Atlantic region has suffered significant economic losses in recent years, including 2003, from FHB epidemics (Griffey et al. 1999), reinforcing the need to accelerate development of FHB-resistant cultivars suited to our area. The Virginia Tech Small Grains Program has been involved in developing scab-resistant SRWW cultivars using both traditional and alternative breeding methods. Traditional methods include topcrossing elite parents to obtain an improved cultivar with disease resistance. This method has proven to be successful in developing the scab-resistant Virginia Tech varieties Roane, McCormick, and Tribute. Alternative breeding methods include the transfer of FHB resistance from unadapted germ plasm to adapted elite varieties via backcrossing and the acceleration of breeding progress using the 'wheat x maize' DH system. This paper evaluates progress made to date using such alternative breeding methods.

Materials and methods. Backcrossing. The first crosses between unadapted, scab-resistant lines and adapted elite cultivars were initiated in 1998. Following these initial crosses, a series of one to five backcrosses were made to elite (recurrent) parents. During each of these cycles, the backcrosses were evaluated for scab resistance in a mist-irrigated greenhouse using the single-floret inoculation technique. At various stages of the backcrossing process, populations were developed from selected individuals and planted at Mt. Holly, VA, under mist-irrigated, scab-inoculated conditions. FHB-infected maize seed was the primary inoculum applied to these populations each year. Scab-resistant populations were bulk-selected in early generations and advanced; head selections were made in later generations and evaluated in headrows.

Doubled haploids. The use of the 'wheat x maize' DH system was initiated in 2000 with nine three-way crosses comprised of diverse scab-resistant parents. Emasculated wheat heads were hand-pollinated with maize pollen and immersed in 100 mg/L 2,4-D solution 1 to 2 days later. Embryos were excised 12-16 days after pollination and cultured in test tubes containing nutrient agar medium. The resulting seedlings were then immersed in 0.1 % colchicine solution, rinsed, transplanted into soil, and vernalized for up to 8 weeks. This process was repeated in 2001 with 10 additional three-way crosses.

Results and discussion. Backcrosses. In 2002, 29 BC1F4 and three BC2F4 headrows were selected and subsequently evaluated in observation yield tests at two locations and in a FHB nursery in 2003. From these lines, 12 lines were selected and advanced for testing in replicated preliminary yield tests at three locations in 2004. Five of these lines also are being tested in the 2004 Uniform Scab Nurseries. Most of these lines had higher yield and lower FHB incidence than recurrent parent Roane, and four lines had FHB incidence levels lower than recurrent parent Ernie (Wilson et al. 2003). FHB severity and index values followed a similar pattern.

In 2003, 124 backcross lines (28 BC1F5, 15 BC2F5, 59 BC2F4, 3 BC3F4, 18 BC4F3, and 1 BC5F3) were selected as headrows and advanced for evaluation in observation yield tests at two locations and in a FHB-screening nursery in 2004. Field and greenhouse FHB-screening data for the most advanced backcross lines are presented in Table 1. Most of the backcross lines were more resistant to scab than their respective recurrent parents in the field test. In the 2002 greenhouse screening, all of the backcross lines were more resistant than their recurrent parent.

Doubled haploids. In 2003, 135 H3 DH lines were evaluated in inoculated, mist-irrigated greenhouse and field tests. Of these lines, 30 were selected for further evaluation in observation yield tests at two locations and in a FHB-screening nursery during the 2003-04 growing season. Twelve of 19 original three-way crosses were represented among these selections. For most of the lines, scab incidence and severity percentages were 30 or less, and type-II resistance ratings were within the resistant to moderately resistant range (Wilson et al. 2003).

References.

• Griffey CA, Chen J, Pridgen T, Chappell M, and Stromberg EL. 1999. Research on Fusarium head blight in the Virginia Tech Small Grains Program. In: Proc 1999 Eastern & Southern Wheat Workers Conference. 2-4 May, Williamsburg, VA. Pp. 95-99. Ann Wheat Newslet 45:281-282
• Wilson JA, Griffey CA, Chen J, Nabati D, and Pridgen T. 2003. Success of alternative breeding methods in transferring Fusarium Head Blight resistance to soft red winter wheat. In: Proc 2003 National Fusarium Head Blight Forum, 13-15 December, 2003, Bloomington, MN (http://www.scabusa.org). Pp. 295-299.

Wheat projects in 2004. [p. 272]

M.M. Alley and W.E. Thomason.

Current research on wheat management. A survey of the micronutrient content of Virginia wheat is being conducted to determine both the tissue and grain levels associated with major soils used for wheat production. Soil, plant, and grain samples will be analyzed from at least 30 fields. In addition, field trials will be conducted to measure crop response to selected micronutrient applications. Results will be utilized to determine if more detailed research is needed on micronutrient fertilization of wheat as well as to establish a data set of grain micronutrient contents for use by food scientists in assessing the nutritional value of Virginia wheat.

Research on bread wheat quality. Grain yield and yield components of promising bread wheat cultivars, produced using previously determined optimal nitrogen management practices, will be measured at three trials in the state. Seeding rate ranges from below optimum to above optimum populations (15 to 35 seeds/row ft) will be evaluated to determine appropriate seeding rates to optimize yield of bread wheat. These cultivars also will be tested for yield response to foliar fungicide treatments and disease reactions will be assessed in untreated versus fungicide-treated plots. Grain samples will be evaluated for milling and baking quality.

Personnel. [p. 272-273]

Dr. Daniel E. Brann retired 1 July, 2002, from Virginia Tech following 28 years of devoted service as Small Grains Extension Specialist. Scientists and grain producers alike have benefited from Dan's unwavering commitment and devotion to the small grains industry, and sincere gratitude is expressed to Dan for his outstanding service and leadership. Dan grew up on a grain crop farm in eastern Virginia, obtained a B.S. in Agronomy from Virginia Tech in 1967, and a Ph.D. in Agronomy from West Virginia University in 1971. Dan was employed as the Extension Grain Crops Specialist at Virginia Tech from 1974 until his retirement. During his career he was recognized academically by being promoted to associate and full professor. The most prestigious of his awards include the Statewide Extension Excellence Award and being selected by Progressive Farmer Magazine as 'Man of the Year in Service to Virginia Agriculture'. He is nationally recognized for leadership in research and implementation of intensively managed wheat. Dan conducted the small grains cultivar trials for Virginia Tech and worked very closely with Virginia's small grains breeding program in germ plasm evaluation and strategic planning. He continued to lead the cultivar-testing program and certain aspects of the extension grains position on a volunteer basis until his replacement was hired. He became active in the National Barley Improvement Committee by filling in for Dr. Josa Costa at the Washington Legislative Meeting and Visits in 2003. He is currently vice president of the Virginia Small Grains Association (VSGA) and Chairmen of its Barley Marketing Committee, a member of Virginia Tech's College of Agriculture and Life Sciences Dean's Advisory Council, a member of the Montgomery County Farm Bureau, and a board member of the Virginia Crop Improvement Association. As Chairmen of the VSGA barley marketing committee, he is aggressively developing new markets for hulless barley in the livestock and ethanol industries. He also farms about 500 acres of grain crops with his dad and nephew in eastern Virginia.

Dr. Wade E. Thomason accepted the position of Extension Grain Crops Specialist at Virginia Tech and joined the faculty of the Crop and Soil Environmental Sciences Department in January 2004. Wade is an Oklahoma native and received his B.S. (1996) in animal science, his M.S. (1998) in agronomy, and his Ph.D. (2001) in soil science, all from Oklahoma State University. He comes to Virginia from the Samuel R. Noble Foundation, Ardmore, OK, where he worked as a crop and soil specialist. At Virginia Tech his responsibilities include leading state-wide extension and research programs in production and management of corn, small grains, and sorghum for grain and silage. Wade's extension role is to conduct the statewide corn hybrid testing program and work coöperatively with the small grains breeder to conduct and publish results from the statewide small grain variety testing program. This information is disseminated to growers, industry, and county extension personnel. Wade's research interests include evaluation of profitable cropping systems, evaluations and testing of multiple classes and varieties of wheat and barley for human food, feed, fuel and value added uses, and cultivar selection and fertilization.

Publications. [p. 273]

• Griffey CA, Rohrer WL, Pridgen TH, Brooks WS, Vaughn ME, Sisson WL, Price AM, Brann DE, and Smid AE. 2003. Registration of Sisson Wheat. Crop Sci 43:1134-1135.
• Schilling AS, Abaye AO, Griffey CA, Brann DE, Alley MM, and Pridgen TH. 2003. Adaptation and performance of winter durum wheat in Virginia. Agron J 95:642-651.