Commercial Corn Research Articles

Quantifying Early-Season Pest Injury and Yield Protection of Insecticide Seed Treatments in Corn and Soybean Production in Ontario, Canada

A 4-yr study was conducted comparing the efficacy and value of fungicide-only (FST), neonicotinoid insecticide + fungicide (NST), and diamide insecticide + fungicide (DST) seed treatments for commercial corn Zea mays L. and soybean Glycines max (L.) Merr. production in Ontario, Canada. Plant stand, plant vigor, above- and below-ground insect injury, and yield were assessed on 160 field-scale experiments. Experiments also assessed early-season insect incidence and abundance using newly legislated thresholds for NST use in Ontario and in-season destructive sampling. Wireworms (Coleoptera: Elateridae) and white grubs (Coleoptera: Scarabeidae) were frequently observed at experimental sites; however, thresholds were rarely met and injury levels rarely led to yield loss. Of 129 and 31 corn and soybean sites, 8 and 6%, respectively, had a positive yield response to NST use. Across all sites, yield response of 0.1 and -0.05 Mg ha-1 was observed with NST use in corn and soybean, respectively; however, the costs associated with NST use were recovered at only 48 and 23% of corn and soybean sites, respectively, based on average grain prices and yields during the study. Infrequent incidence of economic injury and the absence of a consistent yield response to NST and DSTs throughout the 4 yr of the study indicate that widespread use of seed-applied insecticides in corn and soybean is unlikely to provide benefit to producers. These data highlight an opportunity for reducing input costs, environmental loading, and nontarget effects without adverse outcomes for Ontario producers.

Analysis of sorghum content in corn–sorghum flour bioethanol feedstock by near infrared spectroscopy

In the sorghum-growing regions of the United States, some bioethanol plants use mixtures of corn and sorghum grains as feedstocks depending on price and availability. For regulatory purposes and for optimizing the ethanol manufacturing process, knowledge of the grain composition of the milled feedstock is important. Thus, a near infrared spectroscopy method was developed to determine the content of sorghum in corn–sorghum flour mixtures. Commercial corn and sorghum grain samples were obtained from a bioethanol plant over an 18-month period and across two crop seasons. An array of corn–sorghum flour mixtures having 0–100% sorghum was prepared and scanned using a near infrared spectrometer in the 950–1650 nm wavelength range. A partial least squares regression model was developed to estimate sorghum content in flour mixtures. A calibration model with R2 of 0.99 and a root mean square error of cross validation of 3.91% predicted the sorghum content of an independent set of flour mixtures with r2 = 0.97, root mean square error of prediction = 5.25% and bias = −0.49%. Fourier-transform infrared spectroscopy was utilized to examine spectral differences in corn and sorghum flours. Differences in absorptions were observed at 2930, 2860, 1710, 1150, 1078, and 988 cm−1 suggesting that C–H antisymmetric and symmetric, C=O and C–O stretch vibrations of corn and sorghum flours differ. The regression coefficients of the near infrared model had major peaks around overtone and combination bands of C–H stretch and bending vibrations at 1165, 1220, and 1350 nm. Therefore, the above results confirmed that sorghum content in corn sorghum flour mixtures can be determined using near infrared spectroscopy.

Tortilla chips made with white sorghum and corn: Comparison of sensory and physicochemical characteristics with corn‐made commercial products

Tortilla chips made with mixtures of white sorghum and corn were compared with two commercial products made from corn to determine their physicochemical, sensory characteristics, and acceptance. A higher content of white sorghum generated products with dark-red tones, but which were equally fracturable and exhibited the same hardness, when compared to commercial tortilla chips. The total phenolic content ranged from 50 to 75 mgGAE/100g, and the condensed tannins content was higher as the white sorghum content in products increased (559–1,100 µgCE/g), but there was no difference in the antioxidant activity (900–1,250 µMAEAA/g) among the products. Two groups of consumers who were identified rated commercial products best for overall liking, although Group 1 (n = 102 subjects) rated products made entirely with sorghum as second best, and Group 2 (n = 116 subjects) considered that treatment as the worst. The white sorghum content in products did not affect taste and aroma, but affected its appearance and acceptance for some consumers. Practical applications Tortilla chips are snacks that are widely consumed around the world. Developing foods with health potential to consumers are a current trend in the market. Sorghum grains contain compounds that could provide health benefits, although its tannins content could impart negative visual or astringent effects to products made from them. Tortilla chips made entirely with white sorghum contain a higher amount of condensed tannins than products made with corn, these modifies the appearance of chips affecting the liking of consumers. Despite this, a segment of consumers considered that those products were almost as good as commercial corn made tortilla chips.

Tensile Strength and Solubility Studies of Edible Biodegradable Films Developed from Pseudo-cereal Starches: An Inclusive Comparison with Commercial Corn Starch

Edible biodegradable films were prepared from amaranth, buckwheat and commercial important corn starches by casting method. Starch, glycerol and carboxymethyl cellulose (CMC) were used to prepare filmogenic starch solutions in potable luke warm water, followed by ultra-sonication for homogenous mixing of the mixed ingredients. After this, heating was applied to starch based slurried solutions until it turned into gel solutions. These filmogenic gel solutions were then dried and films were peeled off and stored in desiccator. Stored films were analyzed for functional properties viz., tensile strength, solubility and water vapor permeation. Amaranth starch based edible biodegradable films presented considerable clarity values however buckwheat starch and corn starch based films exhibited good tensile strength and better solubility values. Developed edible biodegradable films from amaranth starch were analysed for surface structure examination by SEM. Evaluation of surface revealed uniformity, homogeneity with no surface crack on the surface of developed edible biodegradable films.

Urease inhibitor on performance of corn hybrids in second crop in Sinop-MT

Nitrogen is the most demanded element with the most complex management and with the highest responses in productivity in the corn crop, of the principal source of nitrogen supplies, but the urea is inefficient due to its volatilization. The objective of this work was to evaluate the agronomic performance and the efficiency of the urease inhibitor in formulations containing urea, applied in five different commercial corn hybrids in Sinop - MT. The experimental design was in randomized blocks, in a 3 x 5 factorial scheme with three replications. The first factor consisted of three cover fertilizations: control (without application of fertilizer); fertilization with 250 kg ha-1 of urea and fertilization with 250 kg ha-1 of urea with the presence of the urease inhibitor (UREMAX®) NBPT. The second factor was five corn hybrids: 2B433, DKB255, DKB335, NS45 and SYN522. It was found that all hybrids had greater growth and productivity when they received the urease inhibitor, in relation to the treatment without coverage. The hybrids DKB 255, 2B433 and SYN 522, the treatment with UREMAX® reached the highest productivity. The most prominent hybrid in productivity was DKB 255, which reached 9600 kg ha-1, with UREMAX® in cover fertilization, about 31% more than the treatment without urea coverage, and with gains of 18% in relation to urea.

Morphological, physico-chemical and functional properties of underutilized starches in China

In this study, starches were isolated from different non-conventional sources (acorn, black wheat, buckwheat, coix seed, jiaoyu, kuzhu, longya lily, and naked oat) cultivated in China, and their morphological, physico-chemical, and functional properties were analyzed. Among isolated starches, significant differences (p < 0.05) were observed in morphology, pasting, crystallinity, physico-chemical, and functional properties. After a comparison with commercial corn starch, all these isolated starches presented promising and unique characteristics. The XRD profile of isolated starches presented A-type (naked oat, buckwheat, coix seed, and black wheat), B-type (longya lily, acorn and jiaoyu) and C-type (kuzhu) polymorphic structures. SEM analysis revealed that the starches isolated from different sources showed distinct shapes exclusively globular, elliptic, and polygonal shapes. The high viscosity of jiaoyu and kuzhu starch pastes can be utilized to have an advantage in instant soups and sauces. Hence, the present study will improve the scientific basis on starches from different non-conventional sources, facilitate their utilization in a variety of applications.

Pennycress as a Cash Cover-Crop: Improving the Sustainability of Sweet Corn Production Systems

Commercial sweet corn (Zea mays convar. saccharata var. rugosa) production has a proportionally high potential for nutrient loss to waterways, due to its high nitrogen (N) requirements and low N use efficiency. Cover crops planted after sweet corn can help ameliorate N lost from the field, but farmers are reluctant to utilize cover crops due to a lack of economic incentive. Pennycress (Thlaspi arvense L.) is a winter annual that can provide both economic and environmental benefits. Five N-rates (0, 65, 135, 135 split and 200) were applied pre-plant to sweet corn. After the sweet corn harvest, pennycress was planted into the sweet corn residue with two seeding methods and harvested for seed the following spring. Residual inorganic soil N (Nmin), pennycress biomass, biomass N and yield were measured. The nitrogen rate and seeding method had no effect on pennycress yield, biomass, or biomass N content. The nitrogen rate positively affected Nmin at pennycress seeding, wherein 200N plots had 38–80% higher Nmin than 0N plots, but had no effect on Nmin at pennycress harvest. Control treatments without pennycress had an average of 27–42% greater Nmin. In conclusion, pennycress can act as an effective N catch crop, and produce an adequate seed yield after sweet corn without the need for supplemental fertilization.

Physicochemical Properties and Resistant Starch Content of Corn Tortilla Flours Refrigerated at Different Storage Times.

The tortilla is a foodstuff that has a short shelf-life, causing great losses to the industry. The objective of this work was to evaluate, for the first time, the physicochemical properties and resistant starch (RS) content of flours. These were obtained from nixtamalized corn tortillas made with traditional and industrial (commercial) methods, stored at 4 °C for 7, 15, and 30 days. The flours were characterized by measuring particle size distribution, color, water absorption index (WAI), water solubility index (WSI), viscosity, calcium, and RS content. Additionally, chemical proximate analysis, scanning electron microscopy (SEM), and thermal analysis were conducted. Storage at 4 °C increased the friability of tortillas and shifted the particle size distribution toward a greater content of coarse particles in corn tortilla flours. The commercial corn tortilla flours showed higher WAI and WSI values than the traditional corn tortilla flours. On the other hand, the traditional corn tortilla flours exhibited higher RS content values than commercial corn tortilla flours as well as peak viscosity. X-ray diffractograms revealed the presence of amylose-lipid complexes (RS5) in experimental samples. The thermograms evidenced three endotherms corresponding to corn starch gelatinization and melting of type I and type II amylose–lipid complexes.

First Report of Tar Spot of Corn Caused by Phyllachora maydis in Minnesota

HomePlant DiseaseVol. 104, No. 6First Report of Tar Spot of Corn Caused by Phyllachora maydis in Minnesota PreviousNext DISEASE NOTES OPENOpen Access licenseFirst Report of Tar Spot of Corn Caused by Phyllachora maydis in MinnesotaD. K. Malvick, D. E. Plewa, D. Lara, N. M. Kleczewski, C. M. Floyd, and B. E. ArenzD. K. Malvick†Corresponding author: D. K. Malvick; E-mail Address: [email protected]http://orcid.org/0000-0002-0131-8411Department of Plant Pathology, University of Minnesota, St. Paul, MN 55108Search for more papers by this author, D. E. PlewaDepartment of Crop Sciences, University of Illinois, Urbana, IL 61801Search for more papers by this author, D. LaraDepartment of Crop Sciences, University of Illinois, Urbana, IL 61801Search for more papers by this author, N. M. Kleczewskihttp://orcid.org/0000-0001-5671-6727Department of Crop Sciences, University of Illinois, Urbana, IL 61801Search for more papers by this author, C. M. FloydDepartment of Plant Pathology, University of Minnesota, St. Paul, MN 55108Search for more papers by this author, and B. E. ArenzDepartment of Plant Pathology, University of Minnesota, St. Paul, MN 55108Search for more papers by this authorAffiliationsAuthors and Affiliations D. K. Malvick1 † D. E. Plewa2 D. Lara2 N. M. Kleczewski2 C. M. Floyd1 B. E. Arenz1 1Department of Plant Pathology, University of Minnesota, St. Paul, MN 55108 2Department of Crop Sciences, University of Illinois, Urbana, IL 61801 Published Online:7 Apr 2020https://doi.org/10.1094/PDIS-10-19-2167-PDNAboutSections ToolsAdd to favoritesDownload CitationsTrack Citations ShareShare onFacebookTwitterLinked InRedditEmailWechat Tar spot, caused by Phyllachora maydis Maubl., can be a significant disease of corn (Zea mays L.). Commercial corn hybrids with typical signs and symptoms of tar spot were observed and collected in fields from Fillmore and Winona Counties, Minnesota, in late September and early October 2019. The disease in Fillmore County appeared to be focused in one area of the field about 10 m in diameter with incidence estimated at 90% and severity on individual leaves at and above the ear ranging from 1 to 34%. The field in Winona County had leaves with a similar level of severity on field edges. Signs and symptoms on the epidermis of leaves in both fields consisted of small black, raised, circular stroma (0.5 to 4 mm), primarily on the upper surfaces of leaves. All lesions were assessed, and less than 3% of tar spots were associated with fisheye lesions or chlorotic halos. Microscopic examination of the stroma from both locations revealed asci and oval to ovoid, hyaline ascospores of characteristic size and appearance for P. maydis as described by Parbery (1967). Specifically, 40 randomly selected stroma were dissected from the Fillmore County sample, and ascospores within had an average length of 9.8 μm and width of 6.6 μm. Identity of the stroma from samples in both counties was further confirmed by DNA sequencing. Genomic DNA was extracted from stroma, and a portion of the RNA gene (491 bases) was amplified by PCR using ITS4/ITS5 or ITS1F/ITS4 primers (White et al. 1990). The sequence similarity using BLASTN for all samples was 96 to 100% for four accessions of P. maydis (NCBI GenBank accessions MG881846.1, MG881847.1, KU184459.1, and MK184990.1). Due to the biotrophic, obligate nature of P. maydis, Koch’s postulates were not conducted (Parbery 1967). This confirms for the first time that tar spot of corn caused by P. maydis occurs in Minnesota. These results document an increased distribution of tar spot in the United States since it was first found in 2015 (Ruhl et al. 2016), which includes at least two counties in Minnesota, where it could cause significant economic losses for corn producers.The author(s) declare no conflict of interest.

Prediction of Genetic Gain in Sweet Corn using Selection Indexes

The cultivation of sweet corn is expanding in Brazil, but there are serious constraints about the availability of commercial cultivars. The selection of superior sweet corn genotypes can be performed based on selection indexes based on plant agronomic characteristics. Thus, the objective of this work was to compare selection indexes to select sweet corn genotypes aiming greater productions. The experiment was conducted at the Vegetable Experimental Station of the Federal University of Uberlândia, Campus Monte Carmelo. Eighteen sweet corn accessions (F3 generation) were evaluated. The selection indexes applied to the agronomic characteristics of sweet corn were: direct and indirect, the sum of ranks, desired gains and ideotype indexes. The characteristics evaluated presented significant differences among genotypes, except for stem diameter, prolificacy and grain number per corncob. The coefficients of variation were below 30%, and the genetic parameters were satisfactory for most of the characteristics. The greatest gains with direct selection were in production (21.23%) and productivity of commercial sweet corn ear (15.19%), however, the indirect gains are unsatisfactory for sweet corn selection, and the sum of ranks index provided a balanced distribution of gains. The sweet corn genotypes L2P11, L2P37, P45, L2L5P3, and L5P18 presented a superior performance for the set of characters evaluated.

Chemical and Antioxidant Charaterization of Native Corn Germplasm from Two Regions of Costa Rica: A Conservation Approach.

The cultivation of native corn has decreased in favor of the cultivation of improved commercial corn varieties. This study seeks to evaluate the antioxidant and antibacterial potential of 36 samples of native corn germplasm from the Brunca (BR) and Chorotega (CR) regions of Costa Rica. The main parameters of comparison were the composition of antioxidant compounds, antiradical activity, and microbicidal effect. The total amount of polyphenols in the germplasm (120 mg GAE/100 g d.w.) was not related to the regions from which the samples were obtained. The overall average for antioxidant capacity was 21.20 μmol TE/g d.w. Accessions from the CR region had higher antioxidant capacity. Anthocyanin content was higher in purple accessions and undetectable in white germplasm. Antioxidant capacity was statistically related to polyphenols content (r = 0.714, p < 0.01). The most promising corn accessions in terms of nutraceutical value came from the CR region.

Adapting the APEX Model to Simulate Detasseling in Inbred Corn for Hybrid Seed Production

HighlightsThe APEX model was adapted to simulate detasseling in inbred corn for hybrid seed production.The adapted model satisfactorily predicted detasseling effects on LAI, grain yield, and N content.An inbred corn model could be applied to evaluate best management practices for inbred corns.Abstract. Hybrid seed corn production comprises approximately 10% of the entire corn acreage in the U.S. Because of seed corn’s high economic value, and to maximize yields, seed corn growers often over-irrigate or apply nitrogen (N) fertilizers equal to or in excess of those recommended for commercial hybrid corn. Detasseling female corn inbred lines during hybrid corn seed production is critical to ensure the purity of seeds. In addition to the removal of tassels, detasseling also results in the removal of several leaves, which may lead to reduced seed yields. The objective of this study was to adapt the Agricultural Policy/Environmental eXtender (APEX) model to simulate the detasseling of female inbred corns in hybrid seed production. An APEX inbred corn model was developed to simulate the effects of detasseling and leaf removals on the development of inbred corn, leaf area index (LAI), grain yield, and grain N content. Growth characteristics of inbred corn were parameterized in APEX using data from a field study conducted in Nebraska. Overall, the APEX inbred corn model successfully predicted the effects of detasseling on LAI, grain yield, and grain N content under the conditions of the field experiment. There was a significant correlation between simulated and measured LAI (Pearson r = 0.86 and R2 = 0.74 at p = 0.05). The computed paired t-test and permutation test p-values indicated no significant differences between measured and simulated LAI. The mean simulation percent difference and percent bias (PBIAS) were respectively 4.2% and 4.7%, while measured and simulated LAI values had an average root mean square error (RMSE) of 0.14. The APEX model predicted grain yield with RMSE of 120 kg ha-1, mean simulation percent difference of 0.48%, and PBIAS of 0.26%. Like LAI, predicted grain yields exhibited significant correlation with field data (Pearson r = 0.99 and R2 = 0.97 at p = 0.05). Similarly, computed paired t-test and permutation test p-values indicated no significant differences between measured and simulated grain yields. Grain N content was predicted with RMSE of 6.75 kg N ha-1, mean simulation percent difference of 1.46%, and PBIAS of 2.45%. Predicted and measured grain N content values were correlated (Pearson r = 0.81 and R2 = 0.65 at p = 0.05), while the t-test and permutation test p-values indicated no significant differences between measured and predicted grain N content. Overall, detasseling effects were better predicted for grain yield than for LAI and grain N content as indicated by a Nash-Sutcliffe efficiency (NSE) of 0.92 compared to NSE values of 0.47 for LAI and 0.43 for grain N content. In conclusion, the hybrid seed corn industry could benefit from the application of inbred corn models that could allow growers to evaluate and identify optimal irrigation and N management practices for inbred corn, similar to the benefits that have been obtained with model simulation for commercial hybrid corn grain production systems. Keywords: APEX parameterization, Detasseling, Inbred corn, Leaf area index.

Yield Performance of Corn Under Heat Stress: A Comparison of Hybrid and Open-Pollinated Seeds During a Period of Technological Transformation, 1933-1955

Starting in the 1930s, commercial hybrid corn seeds rapidly replaced the once predominant open-pollinated varieties planted by farmers. By the mid-1950s almost all corn grown in the United States was of hybrid varieties. Observers have argued that the drought tolerant qualities of these hybrids were a major factor driving farmers’ decisions regarding hybrid adoption, but there is little statistical evidence to substantiate this assertion. Hybrid seeds exhibited other attractive qualities, such as improved performance during prime weather conditions, resistance to wind damage, and increased suitability toward mechanized harvesting. Using historical evidence from Zvi Griliches’s archival records, we reconstruct data on hybrid corn adoption and yields at a more disaggregated geographic level than previously available. We match these data with historical weather records to measure the extent to which hybrid seeds mediated the adverse effects of extreme heat. Our findings suggest that hybrid corns grown in Iowa from 1928 to 1942 did exhibit heat tolerance relative to open-pollinated varieties. This result is unique to Iowa as this reduced temperature sensitivity does not appear when comparing hybrid and open-pollinated grown in other states.

Retardation of 4-Hydroxy-2-Transnonenal (HNE), a Toxic Aldehyde Formation by Antioxidants in Heat-Treated Corn Oil at Frying Temperature

The antioxidative properties of four antioxidants such as rosemary extracts (RE), tert-butylhydroquinone (TBHQ), ascorbyl palmitate (AP), citric acid (CA) and their mixtures were investigated on the formation of 4-hydroxy-2-transnonenal (HNE) in commercial corn oil heated at 185°C for up to 6 hours. Among the antioxidants 100 ppm RE and a mixture of 200 ppm tertiary butylated hydroquinone (TBHQ) + 100 ppm ascorbyl palmitate (AP) + 50 ppm citric acid (CA) exhibited excellent antioxidative activity, as determined by the thiobarbituric acid reaction (TBARS) assay, measuring the formations of the secondary lipid oxidation products and by high-performance liquid chromatography (HPLC), measuring the formation of the toxic α, β-unsaturated hydroxyaldehyde HNE after heat treatment of corn oil at 185°C up to 6 hours. TBHQ, AP and CA alone did not show much protective properties. The synergistic effects of TBHQ + AP + CA mixture shown to reduce the formation of HNE after 6 hours heat-treated corn oil by 27%. RE 100 ppm was also found to be a very effective antioxidant, reducing the formation of HNE after 6 hours heat-treated corn oil in the same condition by 29%.

Extraction and Characterization of Starch from Microalgae and Comparison with Commercial Corn Starch

Starch is the main component that consumed one third in the human diet. One-third of starch produced in the world is used in non-food application such as rubbers production and plastic. Plastic produced from starch which called as bio-plastic is biodegradable and helps in reducing the world pollution which non-degradable plastic now endanger the ecosystem either land or water. Microalgal the easy growing and environmental friendly have opened new potential of revolution for starch-based bio-plastic. The small granules of starch produced from microalgae possess an advantage to replace the starch from food-based, as the small granules able to yield a good quality of bio-plastic. In this study, marine microalgae had been studied for its starch content and could reach up to 19% of total starch content. However, in order to ensure the starch produced from marine microalgae is suitable for bio-plastic application, the characteristics of starch had been studied based on the size of starch granules, amylose/amylopectine content, swelling power and solubility and turbidity. These analyses were done with a comparison of corn starch that used widely in the production of bio-plastic. Hence, by determining these crucial characteristics, the application of starch from microalgae could be expended to various sustainable products.

PSXIV-36 Effect of corn variety and amylase enzyme on cattle performance and carcass characteristics

Abstract Four hundred and thirty-three Angus and Angus cross-bred steers (Body Weight 344 ± 13.3 kg) were utilized in this experiment to compare different varieties of grain corn and α-amylase enzyme on feedlot cattle performance and carcass characteristics. Steers were blocked by body weight and breed and randomly assigned to treatments. Treatments consisted of: 1) Commercial commodity corn (CON); 2) Experimental test corn (TEST;), 3) 50:50 blend of CON and TEST corn sources (BLEND), and 4) CON with 5g of α-amylase enzyme added/hd/d (AMZ; Amaize®, Alltech). Steers were slaughtered after 138 days on feed. Feedlot performance, net energy recovery, hot carcass weight, dressing percentage, subcutaneous adipose tissue depth, longissimus muscle area, marbling score, and calculated yield grade data were analyzed as a randomized complete block design using PROC MIXED of SAS. Dietary treatment had no effect (P &amp;gt; 0.20) on BW, average daily gain, feed efficiency, or net energy recoveries. There was a tendency for daily dry matter intake (DMI) to be influenced by treatment: d 0 – d 90 (P &amp;lt; 0.09), d 91 – slaughter (P = 0.11), and d 0 – slaughter (P &amp;lt; 0.08). Dry matter intake was consistently greater for steers receiving the AMZ treatment when compared to all other treatments. Daily DMI for the TEST treatment was consistently lower than DMI for all other treatments. Hot carcass weight (P = 0.56), dressing percentage (P = 0.10), 12th subcutaneous fat depth (P = 0.88), longissimus muscle area (P = 0.84), yield grade (P = 0.91), marbling score (P = 0.76), quality grade (P = 0.67), and the distribution of USDA yield and quality grades (P &amp;gt; 0.74) were similar across treatments. These results indicate the value of the TEST corn as an energy source in feedlot cattle diets is similar to the value of COM corn an energy source.

Evaluation of enzymatic hydrolysis via alcoholic fermentation of corn flour

Abstract The research was concerned with the enzymatic hydrolysis followed by alcoholic fermentation of corn flour. Commercial corn flour purchased from local market contained starch of 87.25%, moisture 11.86% and ash 0.70%. The kinetics of corn flour hydrolysis was performed at 50°C, 65°C and 80°C using commercial thermos table-∞-amylase and ∞-amyloglucosidase. During hydrolysis the residual starch content was decreased with increasing hydrolysis time. The line weaver- Burk plot for enzyme hydrolysis of corn starch for 2.5%, 5% and 10% flour solution showed a Km value of 2.46, 2.27 and 1.73 mg/ml and Vmax values 1.23, 1.21 and 0.96 U/ml for 50°C, 65°C and 80°C respectively. Thin layer chromatography (TLC) was used to detect the presence of dextrose in the hydrolyzates. The Rf (Retention factors) values showed that the starch was mainly composed of dextrose and depended on carrier solvent use for dextrose assessment. When 100% ethyl alcohol used as carrier solvent the Rf value was 0.72 and ethyl alcohol: ethyl acetate= 1:1 the Rf value was 0.65. Both corn flour solution and its enzymatic hydrolysates were fermented with commercial baker’s yeast. Both the cases starch content was decreased and alcohol content was increased during hydrolysis and alcohol production was 3 times more from hydrolysates. The results obtained here will be useful for further research in the production of other value added products like white vinegar from the produced alcohol from con flour.

Temporal and spatial variations of irrigation water use for commercial corn fields in Central Nebraska

The increasing pressure on water resources in Nebraska-US and other agricultural areas requires the implementation of innovative tools and solutions for the governance of water resources and the analysis of water use efficiency. In this vein, this paper presents the application of a remote sensing based soil water balance for the study of water use in agricultural areas. The specific objectives were the identification of the temporal and spatial behavior of the irrigation water use based on the quantification of the water use deviation (irrigation water applied minus irrigation water requirements), as the main indicator and the comparative analysis of the irrigation productivity (crop yield under irrigated field minus crop yield under rainfed condition per volume of water applied by irrigation), WPi, water productivity (harvestable grain per total volume of water applied considering precipitation plus irrigation), WP, and finally water productivity based on evapotranspiration (harvested grain per total volume of water evapotranspired), WPET, in the various management zones analyzed. Additionally, we examined the impact of soil types, local weather and irrigation system (center pivot and furrow irrigation) on these indicators. The study was carried out in three Natural Resources District (Tri-Basin, Central Platte and Lower Niobrara) across Central Nebraska for the period 2004–2012 and comprised over 2000 irrigated corn fields per year. Crop water requirements were estimated using the reflectance-based crop coefficient approach developed in previous research (see Campos et al., 2017) and the field data were reported for each field monitored through cropland data layer by National Agricultural Statistics Service of USDA. The difference between modeled irrigation water requirements and field level irrigation application was significant (p < 0.001) being the water use deviation in generally positive (over irrigation). These results were consistently higher for furrow irrigated fields during the whole analyzed period, reaching up to three times more water applied compared to the required amount. This was expected as surface irrigation systems typically require a higher application depth. This trend changed for the central pivot irrigated fields depending on the climatic conditions, especially in dry years. The analysis of the water use deviation with respect to soil types and weather conditions revealed that the water use deviation is not justified by the biophysical conditions alone. The estimated values of WP and WPi for furrow system was lower compared to center pivot in both NRD’s reaching the maximum value of 1.37 kg m-3 and 3.06 kg m-3 for WP and WPi in Tri-basin respectively for center pivot. In general, the results suggested potential to improve water management in these NRDs in Central Nebraska and reduce pumping potentially saving groundwater resources for drought years and other uses monitoring soil type, weather data and switching to sprinklers system.

Temporal progression of foliar plant diseases in corn hybrids

The environment’s impact on foliar disease growth in annual crops and the various types of differentiation must be investigated to adapt effective disease control strategies. We studied the temporal progression of foliar disease complexes in 14 commercial corn (Zea mays L.) hybrids during the 2015/2016 crop season (Ipameri, Goiás, Brazil). The experiment consisted of 10 blocks and evaluated foliar disease severity using a diagrammatic scale. The evaluations occurred at 47, 53, 59, 74, 81 and 95 days after planting. At each time point, a plant was chosen randomly from each block (10 plants total), and the diseases causing foliar damage were identified. The areas under the disease progression curves (AUDPCs) and yields were calculated. Dependent variables were evaluated using a principal component analysis to study relationships between the hybrids and the disease severity on each leaf (biplot). Heatmaps were used to determine which leaves demonstrated the greatest disease severity and temporal disease progression, and an adjusted linear correlation model was used to predict yield relative to AUDPC. The foliar disease complex consisted of helmintosporiosis, common rust, macrospora leaf spot, cercosporiosis and maize white spot. The Ns90PRO© hybrid showed limited disease progression and; therefore, was considered more resistant and consequently had a lower AUDPC value. The Dow2B610PW© hybrid showed greater disease progression. Agroceres7098PRO2© had a greater yield and consequently a lower AUDPC value, while Lg6050PRO2© had a lower yield and a higher AUDPC value. In general, the more advanced the phenological stage, the more severe the leaf disease; however, disease progression (from plant base to plant tip) was genotype- dependent.

Field Displacement of Aflatoxigenic Aspergillus flavus Strains Through Repeated Biological Control Applications.

A popular pre-harvest strategy to mitigate aflatoxin contamination of corn involves field application of non-aflatoxigenic strains of Aspergillus flavus. The basis of this biological control may involve multiple factors, but competitive displacement of aflatoxigenic strains by the biocontrol strains is a likely mechanism. Three biocontrol strains (NRRL 21882, 18543, and 30797) were applied annually, over a 4-year period, to the same 3.2-ha commercial corn field in the Mississippi Delta, where we monitored their post-release establishment, spread, and persistence. Within 2 months of the first biocontrol application, the percentage of soil-inhabiting aflatoxigenic A. flavus strains in some plots was reduced from 48 to 9% of the population. The frequency of aflatoxigenic A. flavus strains was also significantly reduced in the rest of field. After 4 years, neighboring plots that had never received a biocontrol treatment, and distanced from our treatment plots by at least 20 meters, had less than 20% aflatoxigenic isolates. This significant halo effect might be attributed to movement of soil through tillage operations, but the aflatoxigenicity shift could be detected in the untreated plots within 2 months of the initial applications, at a time when there was no tillage. The A. flavus populations that colonized the grain were also monitored and found to be less than 15% toxigenic in the fourth year for all treatments. Over all treatments and years, less than 2 ppb of aflatoxin was detected, which could be a consequence of the field-wide shift of the inherent A. flavus population to predominately non-aflatoxigenic strains. This study supports the efficacy of using non-aflatoxigenic A. flavus strains as pre-harvest biocontrol, and shows that most of its effectiveness occurs with the first application.