J. J. Wiersma

An Emergence Model for Wild Oat (Avena fatua)

Abstract Wild oat is an economically important annual weed throughout small grain producing regions of the United States and Canada. Timely and more accurate control of wild oat may be developed if there is a better understanding of its emergence patterns. The objectives of this research were to evaluate the emergence pattern of wild oat and determine if emergence could be predicted using soil growing degree days (GDD) and/or hydrothermal time (HTT). Research plots were established at Crookston, MN, and Fargo, ND, in 2002 and 2003. On a weekly basis, naturally emerging seedlings were counted and removed from six 0.37-m2 permanent quadrats randomly distributed in a wild oat–infested area. This process was repeated until no additional emergence was observed. Wild oat emergence began between May 1 and May 15 at both locations and in both years and continued for 4 to 6 wk. Base soil temperature and soil water potential associated with wild oat emergence were determined to be 1 C and −0.6 MPa, respectively. Seedling emergence was correlated with GDD and HTT but not calendar days (P = 0.15). A Weibull function was fitted to cumulative wild oat emergence and GDD and HTT. The models for GDD (n = 22, r2 = 0.93, root mean square error [RMSE] = 10.7) and HTT (n = 22, r2 = 0.92, RMSE = 11.2) closely fit observed emergence patterns. The latter model is the first to use HTT to predict wild oat emergence under field conditions. Both models can aid in the future study of wild oat emergence and assist growers and agricultural professionals with planning timely and more accurate wild oat control. Nomenclature: Wild oat, Avena fatua L. AVEFA

Evaluation of five fungicide application timings for control of leaf-spot diseases and fusarium head blight in hard red spring wheat

The optimum timing of fungicide applications for control of leaf-spot diseases in hard red spring wheat (HRSW) is reported to be at Zadoks growth stage 39 (GS 39; flag leaf collar visible), while the optimum timing for suppression of fusarium head blight (FHB) is at GS 60 (beginning of anthesis). The objectives of this research were the following: (i) to compare five different timings of fungicide applications for control of common leaf-spot diseases and FHB and (ii) to evaluate whether the tested HRSW cultivars could be grouped based on their disease ratings to formulate recommendations for the use of fungicides. Across cultivars, the optimum timing of a fungicide application to control leaf diseases was at GS 60 rather than at GS 39. Waiting until flowering did not sacrifice control of the leafspot diseases or grain yield. The application of one half of the labeled rate of Stratego at GS 15 (fifth leaf unfolded) in combination with the labeled rate of Folicur at GS 60 tended to provide the best control of the leaf-spot diseases and greatest improvement in grain yield and grain quality. The average increase in grain yield with this combination of fungicide treatments was 11%, 31%, and 16% across varieties in 2001, 2002, and 2003, respectively. When the leafspot diseases developed early, as was the case in 2002, a single application at GS 60 was less effective than applications both at GS 15 and GS 60 for cultivars that were rated more susceptible to leaf-spot diseases. Even when differences were detected for disease severity of the leaf-spot diseases at GS 85 (soft dough), no differences were detected for grain yield, grain volume weight, grain protein, or kernel weight between cultivars that were rated more susceptible to the leaf-spot diseases versus those that were rated more resistant.

Sulfur, Protein Size Distribution, and Free Amino Acids in Flour Mill Streams and Their Relationship to Dough Rheology and Breadmaking Traits

ABSTRACT The aim of this study was to analyze sulfur content, protein size distribution, and free amino acids in flour mill streams (FMS) and their associations to dough rheology and breadmaking traits. Break FMS had higher nitrogen and sulfur quantities than reduction FMS. The third break FMS had the highest nitrogen and sulfur contents among FMS but low bread loaf volume partly due to high ash content. Sulfur quantity had greater or equivalent correlations with dough rheology and breadmaking properties compared with nitrogen quantity when the effect of percent ash content was removed statistically. FMS also showed significant quantitative variation in HMW polymeric proteins of the SDS-unextractable fraction that had greater association with sulfur content and dough rheology and breadmaking traits than other protein fractions. Asparagine, which is a major amino acid in flour, was found at higher levels in the third break and third reduction FMS. Ratio of nitrogen to sulfur was significantly correlated wi...

Hard Red Spring Wheat (Triticum aestivum) Tolerance to Postemergence Grass Herbicides1

Eight hard red spring wheat cultivars were tested for tolerance to five postemergence grass herbicides at two locations in Minnesota in 1999 and 2000 at the labeled, one and one-half, or twice the labeled rate. Fenoxaprop plus safener and ICIA 0604 caused the least injury and did not reduce grain yield for most cultivars. Flucarbazone caused intermediate injury and a slight decrease in grain yield for half the cultivars tested. Difenzoquat caused the most injury, regardless of whether the cultivar was genetically sensitive to difenzoquat. Tank-mixing difenzoquat with imazamethabenz reduced injury, even for cultivars that were not genetically sensitive to difenzoquat. Drought stress before application of the postemergence grass herbicides that contain difenzoquat resulted in more potential for crop injury. Excess precipitation combined with high temperatures after application resulted in more potential for crop injury for the other postemergence grass herbicides included in this experiment. Nomenclature: Difenzoquat; fenoxaprop; flucarbazone; ICIA 0604 (proposed common name, tralkoxydim; 2-cyclohexen-[1-one,2-]1-(ethoxyimino)propyl]-3-hydroxy-5-(2,4,6-trimethylphenyl)-(9CI)); imazamethabenz; wheat, Triticum aestivum L. emend. Thell. Additional index words: Crop injury, herbicide tolerance. Abbreviations: HRSW, hard red spring wheat.

Assessing the Impacts of Subsurface Drainage in Northwest Minnesota

Results of field observations of soil water table depth and soil moisture content in two soils of Northwest Minnesota are presented herein. The results showed that drainage is effective in reducing water table and soil moisture content in field to avoid waterlogging. The reduction mainly took place between April and June when snowmelt increased the antecedent soil moisture and when the ET was smaller. The effectiveness of drainage depends on the drainage spacings and soil properties. Poorly drained soils require narrower drainage spacing while relatively good drained soils need wider drainage spacing. Taking 60 cm as the depth of water table above which crop yield would be affected, undrained soil had 32 days in Brooks and 20 days in Crookston that affected the crop yield in 2002. In the drained soils of Brooks the days reduced to 12 and 6 for plots with drainage spacings 24 and 12 m, respectively. In the drained soils of Crookston the days reduced to 9 and 1 for plots with drainage spacings 18 and 5 m, respectively. The soil moisture content in the drained soil was significantly lower than that in the un-drained soil, particularly between depths 2 to 30 cm.

Consumer Knowledge and Horse Preference for Different Colored Oats

ABSTRACT Oats (Avena sativa L.) are used for human and livestock consumption. Currently, the market prefers white hulled oats that have a high test weight, which historically were used for equine feed. Plant breeding programs in the Midwest United States produce both white and yellow hulled oats that meet industry standards; however, there appears to be a market preference for white hulled oats even though the hull is removed before processing for human consumption. The perception for this preference is that the horse industry demands white oats. This two‐part study was conducted to determine if horse owners and managers, or the horses, had a preference for a specific hull color. To accomplish the first objective, a 13‐question survey regarding oat use and preference among horse owners and managers was administered for 6 weeks through the University of Minnesota Horse Extension Team. The 801 survey respondents did not have a visual preference for white or yellow hulled oats (P = .89). For individuals who purchased oats, the most important quality was cleanliness, with color and test weight being the least important. The second objective consisted of two horse‐feeding trials. The horses did express a preference for yellow hulled over white hulled oats (P < .0001). Although horse owners and managers did not indicate a color preference for oats, horses preferred yellow oats. The lack of preference from horse owners and managers suggests that others within the oat supply chain are driving the market to categorize white oats as the premium horse feed. HIGHLIGHTSIt is currently believed that horse owners prefer white hulled oats.When choosing oats, horse owners are most concerned with cleanliness, not color.Horse owners did not indicate a preference for either yellow or white hulled oats.Horses preferred yellow hulled oats over white hulled oats.Owner and horse preference for white hulled oats were not validated.

Influence of Time of Emergence on the Growth and Development of Wild Oat (Avena fatua)

Abstract Successful control of wild oat in cereal crops requires an accurate prediction of the developmental stages of wild oat plants that emerged during the growing season. The main objective of this research was to evaluate wild oat growth and to predict the phyllochron of wild oat plants that emerge at various times in the Red River Valley region of Minnesota and North Dakota. Field experiments were conducted in 2002 and 2003 in Crookston, MN, and Fargo, ND. Four emergence cohorts were established in 4 successive wk. Research plots were arranged in randomized complete blocks with six replications. From the naturally emerged wild oat population, 10 randomly selected plants per plot were evaluated for plant height, leaves on main stem, tillers per plant, total leaves per plant, days to flag leaf emergence and to heading, biomass per plant, and seeds per plant. Hauns numerical cereal development scale was regressed on days after emergence (DAE), day length (DL), growing degree days (GDD), or photothermal units (PTU). Wild oats that emerged first required more time for flag leaf emergence and heading, were taller, and had more biomass, leaves, tillers, and seed production than wild oat plants that emerged later. Wild oat phyllochron intervals were 5.3 d, 94 GDD, or 1,468 PTU, regardless of emergence timing. These data suggest that wild oat phyllochron is primarily driven by air temperature and is relatively stable during the extended emergence period. Later-emerging wild oat plants, although not as competitive as earlier emerging ones, still have the potential to contribute to the seed bank if left uncontrolled. Nomenclature: Wild oat, Avena fatua L. AVEFA.

Land: Hybrid Corn

Crop plant modification through both breeding and genetic engineering have the potential for both improving human welfare and causing problems for people as well as the environment.