SOUTH DAKOTA

South Dakota State University, and USDA-ARSNorthern Grain Insect Research Laboratory (NGIRL)

The Departments of Plant Science and Biology/Microbiology, Brookings, SD 57007, USA.

Personnel changes.

Dr. Fred A. Cholick, former spring wheat breeder and Plant Science Department Head, accepted the position of Director of the South Dakota Agricultural Experiment Station, effective September 1994. Dr. Cholick now oversees research programs of 12 academic departments in two colleges at the University.

Dr. George Buchenau, wheat pathologist, retired from service to the Plant Science Department, effective July 1994. For over 34 years, Dr. Buchenau was active in breeding efforts to improve disease resistance in both spring and winter wheat. In recent years, Dr. Buchenau focused his efforts on development of expert systems to model epidemiology of tan spot.

Spring wheat breeding.

J.C. Rudd, B.G. Farber, G. Buchenau, C.H. Chen, R. Yu, F. Aldana, and K. Ruden.

Production. The 1994 production of hard red spring wheat in South Dakota was 51.5 million bushels from 2 million acres. The average yield was 26 bu/acre compared to an average yield of 27 bu/acre in 1993 and 34 bu/acre in 1992. If there is such a thing as an average growing season in South Dakota, 1994 might fit that description. There were very few record-breaking fields and not too many disasters. In general, moisture was adequate at planting, short during tillering, and adequate during grain fill. Fusarium head blight (scab) caused a yield reduction in the northeast part of the state. Although the area of devastation was not as great as in 1993, both yield and quality of the grain were reduced severely in a significant number of fields. Durum production in the state was 598,000 bushels from 23,000 acres, with an average grain yield of 26 bu/acre.

New Release. SD8073 (SD8052/SD2971) is being released as `Russ'. The pedigree of SD8052 is `ND585/Shield' and the pedigree of SD2971 is `Agt/3/ND441//Wld/BB/4/Butte/5/Len'. Russ is an awned, early maturing, standard height, hard red spring wheat. In performance relative to 'Butte 86' (109 site-years), SD8073 was 2 bushels/acre higher yielding, slightly lower in bushel weight, and similar in height. It is 2 days later heading than Butte 86 and 2 days earlier heading than 'Prospect'. South Dakota trials indicate that SD8073 yields more than Butte 86, Prospect, and 'Sharp'; and similar to '2375'. It appears to be adapted widely and has performed well in all areas tested in South Dakota, as well as in HRSWURN locations. Russ has good resistance to the prevalent races of leaf and stem rust in South Dakota. The probable genes for stem rust resistance are Waldron and/or Sr24. It is heterogeneous for Hessian fly resistance (H18), with approximately 50 % of the plants resistant to the Great Plains biotype. Based on 1993 and 1994 performance data, Russ is similar to Butte 86 for Fusarium head blight resistance. Russ is a strong mixing wheat with medium protein content and good bread making properties.

SD0010 will be increased in 1995 with the intent to release in 1996. SD0010 is an awned, early maturing, semidwarf, hard red spring wheat. Originating from Pioneer Hi-bred International, the pedigree is `YW352/SBZ004A (SBF0089)'. In performance relative to '2375', SD0010 is similar yielding and slightly shorter and has similar maturity and better straw strength. It has about 0.5 % higher protein than 'Prospect' and 0.5 % lower protein than Butte 86. The milling and breadmaking qualities of SD0010 are similar to those of 'Grandin'.

Germplasm. SD8070 (Guard/Sharp) is an awned, early maturing, standard height, hard red spring wheat. It was released as a source of Hessian fly (H18) and tan spot resistance in a good agronomic spring wheat background. It was in South Dakota State University trials from 1991 to 1993 and in the Uniform Regional Hard Red Spring Wheat Nursery in 1992 and 1993. It was eliminated from further testing because of stem rust susceptibility. In performance relative to 'Sharp', SD8070 is similar in yield, 1 pound lower in bushel weight, similar in maturity, and similar in height and has better straw strength. Milling and breadmaking qualities of SD8070 are very similar to those of 'Butte 86'. SD8070 has excellent foliar disease resistance as measured by field observations of leaf area duration. It shows good resistance to Pyrenophora tritici-repentis (tan spot) in field trials under natural infection and in greenhouse seedling screening. Greenhouse screening indicates that SD8070 has a similar level of tan spot resistance as 'Erik' and 'Karl'. Hessian fly screening by Dr. J.H. Hatchett, USDA-ARS, Manhattan, Kansas, indicates that SD8070 is homogeneous for resistance to the Great Plains biotype.

SD-SWGP1, SD-SWGP2, SD-SWGP3, SD-SWGP4, and SD-SWGP5 are synthetic hexaploid wheats that have good resistance to P. tritici-repentis (tan spot). They were developed by Dr. Christine Curtis, Indiana University Medical Center, Indianapolis, Indiana, by crossing durum wheats with two Triticum tauschii accessions and then doubling the ABD hybrids with colchicine. The two T. tauschii accessions (Clae 10 and Clae 12, both from Iran) had been identified previously as tan spot resistant by screening conducted by Dr. George Buchenau, SDSU, from a collection of accessions obtained from the USDA-ARS National Small Grains Collection, Aberdeen, Idaho. The synthetic hexaploid wheats have a stable chromosome number of 42. They are extremely late and tall (9-12 days later and 30 cm taller than 'Butte 86') and have a fragile rachis and tough glumes. The pedigrees are: SD-SWGP1

(Monroe/Clae 10), SD-SWGP2 (Monroe/Clae 12), SD-SWGP3 (Renville/Clae 10), SD-SWGP4 (Renville/Clae 12), and SD-SWGP5, (Lloyd/Clae 10).

High temperature tolerance.

F. Aldana and J.C. Rudd.

Eight hard spring wheat lines of diverse origin were crossed in a diallel mating design. The parents were chosen for their high temperature tolerance in their area of adaptation. Yield trials of the parents and F₂ hybrids were planted on three different dates. Each successive yield trial grew and matured under a higher temperature regime. The experiments were conducted both in Cd. Obregon, Mexico, and South Dakota, USA. The effect of the high temperature stress was significant, as indicated by the decrease in grain yield with delayed planting. The diallel analysis indicated that GCA was significant for yield and yield components at most of the planting date-locations. The importance of GCA also is supported by a comparison of the yield of the parents, per se, and the yield of their crosses. The data from both locations showed that the rank of the parents, per se, was very similar to their rank by GCA. SCA was also significant for most traits but was always considerably lower than GCA. Kernel weight was the only yield component for which there was no significant SCA.

Near-infrared reflectance spectroscopy.

K. Ruden and J.C. Rudd.

We are investigating the feasibility of using whole seed NIRS for estimation of breadmaking quality parameters. Grain harvested from South Dakota and regional yield trials was used to develop calibration equations. The calibrations for protein content appear to be good (R² = 0.95), and other calibrations are being developed. Although we will continue to use standard procedures to measure breadmaking quality of our advanced lines, we will use NIRS as a rapid nondestructive measurement of early generation and preliminary nursery material.

Wheat anther culture.

C.H. Chen and R. Yu.

A cultivar-specific toxin (MW @ 14 KD) was isolated from a culture filtrate of P. tritici-repentis, the pathogen of wheat tan spot disease. Capacities of callus/embryoid initiation in anthers cultured on W14 medium with the toxin were impaired significantly as compared to those grown on toxin-free medium. In anther cultures of F₁s of crosses between toxin-insensitive cultivars and toxin-sensitive cultivars, callus induction rate was related negatively to toxin concentration in the media. Toxin infiltration testing on regenerated plants revealed that toxin or culture filtrate in the media exerted an effective selection pressure on cultures for microspores of insensitive genotypes, resulting in far more toxin-insensitive than sensitive regenerants. Efficiency of double haploid regeneration may be improved, if surviving calli/embryoids are treated with 50-100 mg/L colchicine in a differentiation medium for 2 days.

Publications.

Aldana F, Rudd JC, Cholick FA, and Rajaram S. 1994. Diallel analysis of diverse spring wheat lines for grain fill under high temperature. Agron Abstr:111.

Del Blanco IA. 1994. Inheritance and diallel analysis of resistance to Fusarium head blight in wheat. MS Thesis. SD State Univ., Brookings.

Del Blanco IA, Rudd JC, Buchenau GW, and Cholick FA. 1994. Fusarium head blight resistance in spring wheat. In: North American Wheat Workers Workshop (Shroyer J. ed). March 7-9, 1994, Kansas City, MO.

Farber BG and Rudd JC. 1994. Mechanical mass selection for test weight in hard red spring wheat. Agron Abstr:111.

Ruden KR, Rudd JC, Kephart KD, and Hareland GA. 1994. Near-infrared reflectance spectroscopy analysis of hard red spring wheat quality. Agron Abstr:111.

Yu R, Chen CH, Cholick FA, Buchenau GW, AND Rudd JC. 1994. Anther culture selection for tan spot resistance in spring wheat. Agron Abstr:203.

Winter wheat breeding.

S.D. Haley, R.A. Schut, and F. Hakizimana.

Production. The 1994 winter wheat crop in South Dakota would be characterized best as average and variable. Total production was estimated at 43.2 million bushels from 1.3 million harvested acres (1.7 million planted acres) for an average of 32 bu/acre. This yield level is 18 % less than the crop in 1993 (39 bu/acre) and 6 % less than the 5-year average (34 bu/acre). In most areas, good soil moisture was present at planting and excellent fall stands were realized. Overall, winter survival was adequate, except for a significant number of summer-fallow plantings in the central part of the state (most notably Stanley Co.), where sufficient snow cover was not achieved. In many of these cases, fields were completely lost or stands were sufficiently reduced to merit replanting with spring wheat. Aside from this winter injury, the most significant factor reducing yields statewide was a 2-week period of hot and dry weather (from mid- to late-May) that hastened heading of some varieties and caused sterility problems. Damage from this pre-anthesis stress was offset partially in many areas by good rains in early June that carried the crop toward maturity. Because of the dry conditions experienced during spring, foliar disease pressure was lower than average. Although wheat streak mosaic and barley yellow dwarf viruses were not major problems in 1994, farm programs that promote early winter wheat planting will continue to lead to increased potential for insect-vectored viral disease problems.

Breeding program. In 1994, the winter wheat breeding program conducted testing at eight sites in South Dakota. These environments included both Aurora and Brookings (Brookings Co.), Highmore (Hyde Co.), Selby (Walworth Co.), Winner (Tripp Co.), Wall (Pennington Co.), and both irrigated and dryland environments at the Dakota Lakes Research Farm east of Pierre (Hughes Co.). In addition to sites with breeding nurseries, the South Dakota Crops Performance Testing (CPT) Variety Trial (coordinated by Dr. Robert G. Hall, with assistance provided by personnel at the West River Agricultural Research Center in Rapid City and the SDSU Winter Wheat Breeding Program) was planted at eight other sites. These environments included Sturgis (Meade Co.), Ralph (Harding Co.), Bison (Perkins Co.), Hayes (Stanley Co.), Oelrichs (Fall River Co.), Martin (Bennett Co.), Platte (Charles Mix Co.), and Watertown (Codington Co.).

Several significant changes in program operation were made in 1994. Standardized yield trial formats were implemented to improve program flow, line selection from bulk populations (for head rows) was accelerated 2 years from the F₅ to F₃ generations, and a breeding site was added near Wall for fall 1993 planting. For the fall 1994 planting, testing site changes included repositioning of the Tripp Co. breeding site to the town of Ideal, addition of a small breeding site at the Northeast Research Farm near Watertown, and addition of testing sites for the Advanced Yield Trial (AYT) at Bison (in cooperation with Clair Stymiest and John Rickertson, Rapid City) and Mead, Nebraska (in

cooperation with Dr. P. Stephen Baenziger, University of Nebraska-Lincoln). Methods for data collection and analysis also were improved with integration of a bar code reader for yield trial processing, modification of a seed cleaner to allow rapid test weight determination on all test plots, and utilization of statistical software to design and analyze unreplicated yield trials (modified augmented designs) and to remove spatial variability within yield trials (nearest neighbor analysis). Grants were obtained to upgrade the project greenhouse, with supplementary high pressure sodium lighting and an evaporative cooling system. Improvements will allow for greater seed production from crosses and F₁ increases and more rapid generation advance.

New releases and preliminary increases. `Nekota' (tested as NE88427) was released to seed producers for fall 1994 planting. Nekota was derived from the cross `Bennett/TAM 107' made by the University of Nebraska Wheat Breeding Program in 1982. It was identified as a promising line in Nebraska and subsequently entered in the South Dakota Crops Performance Testing (CPT) Variety Trial in 1993 and 1994. Nekota was released because of superior yield performance and test weight patterns in South Dakota and was so named to acknowledge the interstate cooperation that resulted in its release.

Nekota is a medium height semidwarf (1 inch shorter than Alliance, 1 inch taller than TAM 107 and Vista) with good winter hardiness and an intermediate length coleoptile (similar to that of TAM 107, longer than those of Alliance and Vista). Nekota is susceptible to wheat streak mosaic virus, moderately resistant to stem rust, moderately susceptible to leaf rust, and moderately resistant to tan spot. Under South Dakota environments, Nekota is 2 days earlier than Arapahoe, 1 day earlier than Alliance and Vista, and 3 days later than TAM 107. Averaged over 1993 and 1994 (22 environments), Nekota (50.6 bu/acre) yielded less than Alliance (51.4 bu/acre) but was superior to Arapahoe (49.7 bu/acre), Vista (48.9 bu/acre), and TAM 107 (46.7 bu/acre). Nekota also has demonstrated exceptional test weight characteristics in South Dakota (60.8 lbs/bushel), having greater test weight than Arapahoe (59.3 lbs/bushel), Vista (59.1 lbs/bushel), Alliance (58.9 lbs/bushel), and TAM 107 (58.6 lbs/bushel).

Two advanced experimental lines were under small-scale increase in 1994. One of these, SD89119 (Brule/Agate), continued to show promise in statewide tests in 1994. Because of excessive impurity observed in the increase block (mixture of red and white head types), 1,000 white heads were selected for head row purification in 1995.

Breeding support projects. The greenhouse crossing program focused on germplasm enhancement for leaf spotting resistance (tan spot or Septoria), wheat streak mosaic virus and wheat curl mite resistance, barley yellow dwarf virus resistance, leaf rust resistance, and hard white grain characteristics. A special project to utilize dominant male sterility to construct composite cross populations (for tan spot resistance, hard white winter wheat, and grain protein content) will be continued.

Evaluation of germplasm exhibiting a dark-colored straw characteristic will be expanded to include field evaluation of a more comprehensive collection of germplasm from the National Small Grains Collection (272 germplasm accessions) and optimization of greenhouse and growth chamber conditions to promote expression of pigmentation under controlled environments.

A new graduate student (Hakizimana) has begun a thesis research program to evaluate methodology for coleoptile length evaluation and characterize coleoptile length of Great Plains germplasm resources.

Wheat pathology.

M.A.C. Langham and D.J. Gallenberg.

General. The incidence and severity of wheat diseases present in South Dakota during 1994 were typical of most years, with the exception of a high incidence of wheat scab, primarily in the spring wheat production area. High moisture levels

during the summer were clear contributing factors to the scab incidence. Other wheat diseases that were noted included tan spot, wheat streak mosaic (WSM), and barley yellow dwarf (BYD). Weather conditions during fall, 1994, developed in a pattern that historically favors the development of WSM and BYD and may indicate an increased incidence in these diseases during spring, 1995.

Wheat streak mosaic virus. Inoculation of six hard red winter wheat cultivars with wheat streak mosaic virus (WSMV), before or after vernalization, was utilized to compare the effects of inoculation on growth and yield characteristics in greenhouse studies. The number of tillers per plant, height of the primary tiller, number of filled spikelets on the primary tiller, number of kernels per plant, number of kernels per tiller, average kernel weight, and total kernel weight per plant were measured. All plants inoculated with WSMV became symptomatic 7 to 14 days after inoculation, and the plants that were inoculated with buffer remained free of symptoms throughout the study. All responses, except number of tillers per plant, were affected significantly by WSMV infection. Reductions in the total yield of the plants ranged from 16.4 % in prevernalization inoculated Triumph 64 to 84.5 % in postvernalization inoculated Rose. The total yield of all but three of the cultivar and inoculation combinations was reduced more than 50 %. Rose and Triumph 64 were more affected by postvernalization infection. Siouxland was more affected by prevernalization inoculation, and the responses of Abilene, Arapahoe, and Brule varied depending with the yield and growth characteristic analyzed. (Langham and Gallenberg)

Wheat entomology.

W.E. Riedell and R.W. Kieckhefer (USDA-ARS NGIRL).

Cereal aphid infestations continue to have considerable impact upon productivity and profitability of U.S. agriculture. It is estimated that cumulative yield loss and treatment costs for Russian wheat aphids alone have amounted to over $400 million from 1987 to 1992. In an effort to develop new and better ways to manage wheat crops to reduce the plant damage potential and yield loss caused by cereal aphid infestations, ARS scientists at the Northern Grain Insects Research Laboratory conducted a study designed to elucidate the physiological mechanisms that cause yield loss in aphid-damaged plants. The results of the 1994 study revealed that root growth was reduced significantly by leaf feeding damage caused by three different aphid species (Russian wheat aphid, greenbug, and bird cherry-oat aphid), suggesting that crop management protocols that bolster root growth would help plants overcome aphid infestation damage and yield loss. These results substantiate previous findings indicating that crop management practices that promote root growth and function play important roles in improving plant tolerance to aphid damage without using insecticides. These results should be good news to farmers who want to reduce insecticide inputs in their wheat farming operations.

Soil fertility and production research.

H.J. Woodard, A. Bly, and D. Winther.

Three experimental sites were selected in Jones County, SD, on a clay loam soil to determine the effect of P application rates in either tilled or reduced-tilled sites. Four rates of P (15, 29, 58, and 115 kg/ha) as liquid ammonium polyphosphate (10-34-0) were applied with modified anhydrous ammonium applicator knives set at 25 cm apart and perpendicular to the planting direction of either tillage treatment. Recommended levels of N were applied to these P rates to support a yield goal of about 3,400 kg/ha. Two sets of control treatments, with and without recommended N, also were compared. Arapahoe or Dawn hard red winter wheat (HRWW) was planted with either a hoe drill (which made a small planting furrow) with a 25 cm row spacing or with a small plot no-till drill set for a 18 cm row spacing in a separate set of tillage strips.

The P treatments and the two seed planting methods had significant effects on parameters measured for all three sites. The early shoot weight and culm number generally increased incrementally for each increase in P application rate for both planting methods at all sites. The slope of the yield increase was positive and linear, indicating that P was still limiting to yield responses even at the high P treatment. This was expected, because the soil test P level was `low-medium'. However, the greatest increase in grain yield seemed to occur when N was applied to the P control treatment (0 kg P/ha) and also when the 15 kg P/ha rate was applied along with a recommended N application. Tillage had little influence on parameter measurements, because adequate soil moisture was available throughout the growing season.