Showing papers by "Scott D. Haley published in 2003"

Antioxidant properties of bran extracts from Trego wheat grown at different locations.

Abstract: The effects of growing conditions during the grain-filling period, including high temperature stress, total solar radiation, and average daily solar radiation, on the antioxidant properties of Trego wheat were evaluated. Bran extracts were prepared from Trego wheat, grown at four nonirrigated and one irrigated location in Colorado, and compared for their radical scavenging activities against ABTS*+ and DPPH*, Fe(2+) chelating capacities, and total phenolic contents. Significant differences in radical scavenging activities, chelating capacities, and total phenolic contents were detected among Trego bran samples grown at different locations, suggesting that growing conditions may influence the antioxidant properties of wheat. The bran sample obtained from Fort Collins had the strongest scavenging activity against either ABTS*+ or DPPH* radicals and the greatest chelating activity, whereas the highest total phenolic content was detected in bran samples from Walsh, indicating that each antioxidant activity may respond to the environmental changes differently. Positive correlations were detected between the DPPH* scavenging activity and either total solar radiation (r = 0.97, p = 0.03) or average daily solar radiation (r = 0.97, p = 0.03). In addition, HPLC analysis detected the presence of ferulic, syringic, vanillic, p-hydroxybenzoic, and coumaric acids in wheat bran. Additional research is needed to further investigate the effects of environmental conditions and the interactions between genotype and environmental factors on the antioxidant properties of wheat to promote the production of wheat with improved antioxidant properties by optimizing the growing conditions for a selected genotype.

Above winter wheat

Abstract: Above, a hard red winter wheat (Triticum aestivum L. em. Thell.), is adapted for dryland production in the west central Great Plains of the United States. It carries a nontransgenic source of tolerance to imidazolinone herbicides derived by mutation induction with sodium azide. Above was developed cooperatively by the Colorado and Texas Agricultural Experiment Stations and released to seed producers in September 2001. Key words: Triticum aestivum, wheat (winter), cultivar description, herbicide tolerance

GPFARM Plant Model Parameters: Complications of Varieties and the Genotype X Environment Interaction in Wheat

Abstract: The USDA–ARS Great Plains Framework for Agricultural Resource Management (GPFARM) decision support system was developed to assist Great Plains producers in making economically viable and environmentally sound strategic plans for whole farm and ranch systems. A major user requirement for GPFARM is to supply the default plant parameters required to simulate crop growth. Developing this plant parameter database is difficult because varietal differences, caused by a genotype by environment (G . E) interaction, increases parameter uncertainty and variability. This article examines species–based plant parameter sets for simulating winter wheat (Triticum aestivum L.) yield responses, explores the significance of the G . E interaction on simulating varietal grain yield, and investigates whether simple adjustments to a species–based plant parameter database can improve simulation of varietal differences across environments. Three plant parameter sets were evaluated against observed yield data for six locations in eastern Colorado: (1) the Default parameter set used best estimates from EPIC–based plant parameter databases, (2) the Dryland Agroecosystems Project (DAP) parameter set further calibrated the default plant parameters against observed yield data for Colorado, and (3) the Theory parameter set modified DAP parameters based on whether irrigated or dryland conditions were simulated. The Theory parameter set simulated yield the best when pooling varieties over environments and locations. However, no parameter set could simulate all the different varietal yield responses to environmental conditions (irrigated or dryland) due to the diverse G . E interactions. The Theory parameter set best simulated the wheat variety TAM 107 across diverse locations, with little bias for either irrigated or dryland conditions. Simple adjustments to a few plant parameters based on whether dryland or irrigated conditions were simulated improved the species–based plant parameter approach used in GPFARM. However, until a better mechanistic representation of the G . E interaction is incorporated into existing plant growth models, opportunities for improving yield response to environmental conditions and management will be limited.

AP502 CL winter wheat

Abstract: AP502 CL, a hard red winter wheat (Triticum aestivum L. em. Thell.), is adapted for dryland production in the west central Great Plains of the United States. It carries a n ontransgenic source of tolerance to imidazolinone herbicides derived by mutation induction with sodium azide. AP502 CL was developed cooperatively by the Colorado and Texas Agricultural Experiment Stations and released to seed producers in September 2001. Key words: Triticum aestivum, wheat (winter), cultivar description, herbicide tolerance.