University of Idaho
Plant and Soil Science Department, Moscow, ID 83343 and the Agricultural Experiment
Station, P.O. Box AA, Aberdeen, ID 83210, USA. R. Zemetra, E. Souza, S. Guy, S. Quisenberry, P. Berger, M. Lauver, J. Windes, J. Hansen, P. Shiel, M. Rafi, F. Mohammad, and L.A. Mercado.
Production. The 1994 Idaho winter wheat production was 57 million bushels, a 15 % decrease from 1993. The decrease can be attributed to a reduction in acres planted and harvested. The average yield was lower than that in the previous year. Below-average precipitation and above-average temperatures for the late spring and early summer were the primary reasons for the reduction in yield. Because of the climatic conditions, losses from disease were minimal. Wheat streak mosaic was observed in southeastern Idaho. The outbreak of WSMV was due to the presence of 'green' spring wheat in the field when the winter wheat was planted. Statistics for Idaho winter wheat production for the last 5 years are shown below. ______________________________________________________________ Year Acres planted Acres harvested Yield Prod. (bu) x 1,000 x 1,000 bu/ac x 1,000 ______________________________________________________________ 1990 960 920 75 69,000 1991 870 700 70 49,000 1992 870 800 65 52,000 1993 920 850 79 67,000 1994 840 790 72 57,000 ______________________________________________________________
Personnel. M. Rafi completed his Ph.D. and is currently a postdoctoral research associate in plant physiology at the University of California, Davis. M. Fida completed his Ph.D. and returned to his position at the University of Peshwar, Pakistan. L.A. Mercado completed her M.S. degree.
Germplasm releases. Four dwarf bunt resistant hard red winter wheat germplasm lines were released. IDO352, IDO364, IDO443, and IDO444 possess unique types of dwarf bunt resistance.
Transformation. Successful transformation of two commercial soft white winter wheat cultivars was achieved using particle gun transformation. Cotransformation was used to transfer either a BYDV-cp gene or a WSMV-cp gene with the bar gene for initial selection. Presence of the BYDV-cp gene and WSMV-cp gene were confirmed by PCR. Expression of the WSMV-cp gene was confirmed by western blot.
Snow mold tolerance. Two years of studies were concluded at Tetonia, Idaho, to select for total nonstructural carbohydrates (TNC), a possible causal factor in snow mold tolerance. Genotypes varied significantly for TNC level, percent spring stand (survival), and plants per meter. The heritability of fall TNC levels was 52 % in a `Manning*2/Survivor`-derived population and 84 % in a `Blizzard*2/Sumner`-derived population. However, TNC levels correlated with survival in only the `Manning*2/Survivor` population. TNC may be useful as a selection tool in populations where a large degree of variation exists for snow mold tolerance.
Russian wheat aphid. Changes in the biological processes of D. noxia and resistant and susceptible wheat genotypes were studied. Various densities of aphids were used in time-course experiments monitoring modifications in biological processes of the insects and plants. Reproductive rates and population development of D. noxia were significantly higher when fed on the susceptible cultivar `Stephens` compared with resistant genotypes, PI 137739, PI 140207, and PI 262660. Reproductive rates of D. noxia significantly decreased as aphid density and length of aphid feeding increased. However, D. noxia populations increased as aphid density and length of aphid feeding increased. A significant reduction in total chlorophyll content was observed in resistant genotypes after aphid feeding and could have been caused by increased aphid probing on resistant genotypes. Diuraphis noxia feeding caused modifications in protein profiles of both resistant and susceptible genotypes. Increased expression of the 32.0, 33.0, and 35.0 kD polypeptides in the resistant genotype might play a role in the plant defense mechanism.
Publications. Mercado LA. 1994. Parental diversity of North American hard red spring wheat cultivars. M.S. thesis. University of Idaho, Moscow, Idaho. Mohammad F. 1994. Influence of total nonstructural carbohydrates on snow mold tolerance in winter wheat. Ph.D. dissertation. University of Idaho, Moscow, Idaho. Rafi M. 1994. Biotic and abiotic stress responses in wheat (Triticum aestivum L.). Ph.D. dissertation. University of Idaho, Moscow, Idaho. Schroeder-Teeter S, Zemetra RS, Schotzko DJ, Smith CM, and Rafi M. 1994. Monosomic analysis of Russian wheat aphid (Diuraphis noxia) resistance in Triticum aestivum line PI137739. Euphytica 74:117-120. Souza E, Kruk M, and Sunderman DM. 1994. Association of sugar-snap cookie quality with high molecular weight glutenin alleles in soft white spring wheat. Cereal Chem 71:601-605. Souza E, Windes JM, Sunderman DW, Whitmore J, Kruk M, and Goates B. 1995. Registration of `Bonneville` hard red winter wheat. Crop Sci (In press). Windes JM, Souza E, Sunderman DW, and Goates B. 1995. Registration of four dwarf bunt resistant wheat germplasm: Idaho 352, Idaho 364, Idaho 443, and Idaho 444. Crop Sci (In press). Zemetra RS, Liu CT, Kronstad WE, Lauver M, and Haugerud N. 1995. Registration of `Lambert` wheat. Crop Sci (In press).
University of Illinois
Departments of Agronomy and Plant Pathology, Urbana, IL 61821, USA. F.L. Kolb, E.D. Nafziger, A.L. Rayburn, C. Gourmet, and T.K. Hoffman, Department of Agronomy; and W.L. Pedersen, Department of Plant Pathology. Production Farmers in Illinois planted 1.115 million acres (451,000 hectares) of soft red winter wheat in the fall of 1993. Planting conditions were poor: wet weather delayed harvest of the previous crops and delayed wheat planting. Fall growth and winter survival were below average, and 215,000 acres (87,000 ha) or 19 % of the crop acres were abandoned. Spring weather in 1994 was quite favorable, with very little disease development. The dry weather, with moderate temperatures during May and early June, delayed crop development and harvest slightly, but resulted in excellent grain fill. The state average yield was 56 bushels per acre (3,770 kg per ha). Fall planting conditions were excellent in 1994, and the planted area for the 1994-95 crop stands at 1,500,000 acres (607,000 ha). Growing conditions since planting have been very good. In mid-February, 85 % of the crop was rated as excellent or good.
Cultivar evaluation. Cultivar comparisons were planted at six locations, with an average of about 60 entries per location. Entries consisted of advanced lines from the University of Illinois breeding program, public varieties, and privately-labeled entries. Yields reflected the good growing conditions, with trial average yields ranging from 51 bushels per acre (3,440 kg/ha) at Dixon Springs, to 94 bushels per acre (6,300 kg/ha) at Urbana. A report of performance of commercial cultivars was distributed in early August. Copies are available on request. (E.D. Nafziger)
Cultivar development. Replicated performance trials to evaluate experimental breeding lines were conducted at three locations. About 130 experimental breeding lines were evaluated. Approximately 115 preliminary breeding lines also were evaluated in replicated performance trials at two locations. Two lines, IL84-4046 and IL85-3132-1, were released in 1995 for brand labelling. (F.L. Kolb)
Effect of BYDV on yield and growth of soft red winter wheat. The second year of an experiment to assess the effect of barley yellow dwarf virus (BYDV) on the yield and growth of eight winter wheat cultivars was conducted. A split-plot design was used with insecticide-sprayed (Cygon), naturally infected and fall inoculated treatments as the main plots and the eight cultivars as the subplots. Fall inoculation caused 19 % - 36 % yield reductions compared to Cygon sprayed plots. When natural infection and sprayed treatments were compared, no differences were found in the first year, but in the second year, natural infection caused a 9 % - 14 % yield reduction for three of the cultivars tested. In addition to grain yield, we are examining the effect of BYDV on the growth rate throughout the growing season by sampling the total aboveground biomass on weekly intervals. In both years, BYDV reduced the total biomass accumulation. A nonlinear growth function (Richard's Function) is being fitted to the data to compare growth rates of cultivar by treatment combinations. (F.L. Kolb and T.K. Hoffman)
Effect of BYDV on root growth of soft red winter wheat cultivars grown in the greenhouse. The same eight cultivars being tested in the field are being studied in the greenhouse to determine if genetic differences exist for root growth characteristics and to determine the effect of BYDV on root growth. Cultivars were grown in an aeroponic mist box in a split plot design with BYDV and control treatments used as whole plots and cultivars used as subplots. BYDV reduced root length and root/shoot ratio for all cultivars and increased the total number of roots for two of the cultivars. Cultivars differed in root length, number of roots, and root/shoot ratio. (F.L. Kolb and T.K. Hoffman)
Use of a seed treatment insecticide to control barley yellow dwarf virus in soft red winter wheat. Control of BYDV by a systemic seed-treatment insecticide, imidacloprid (i.a.), was evaluated in 6-row plots of four soft red winter wheat cultivars. Three rates of the insecticide (0.6, 1.2, and 1.8 g a.i. kg-1 seed) and untreated seeds were used. All insecticide treatments decreased the percentage of infected plants, but 1.8 g a.i. kg-1 seed (the highest rate of insecticide evaluated) provided the most protection against BYDV infection. Yield increases of up to 21 % were observed in treated plots of a susceptible cultivar inoculated with viruliferous aphids carrying BYDV-PAV-IL. Uninoculated, insecticide-treated plots also showed an average yield increase of 14 % compared to uninoculated untreated plots. For all cultivars, yield was correlated negatively with the percent disease incidence and positively with test weight and the calculated number of seeds per tiller. (C. Gourmet and F.L. Kolb)
Molecular cytogenetics. Twelve paired near-isolines were analyzed using RAPDs. The lines of each pair were genetically similar except for the presence or absence of the 1RS-1BL translocation. Three lines containing the 1RS-1AL translocation were also analyzed. One hundred and twenty arbitrary sequence primers were used to amplify DNA isolated from the paired near-isolines. Two of the primers were found to amplify rye specific DNA fragments. These same fragments also were found in the 1RS-1AL translocation lines. As more random primers are analyzed, additional 1RS marker loci will be identified. These loci then will be used to produce a RAPD-based saturation map of the 1RS segment in wheat. Such a map will aid in the identification of loci, both beneficial and deleterious, found on the 1RS segment. (A.L. Rayburn)
Personnel. Anna Hewings, USDA-ARS Cereal Virologist located at Urbana, Illinois, accepted a position as Associate Director for the Midwest Area, USDA, in Peoria, Illinois. Her position has not been refilled. Catherine Gourmet completed her Ph.D. under the direction of F.L. Kolb and accepted a postdoctoral position with A. Lane Rayburn at the University of Illinois. Catherine's Ph.D. research was on several aspects of BYDV tolerance in oat and wheat.