Document Type

Dissertation - University Access Only

Award Date

2012

Degree Name

Doctor of Philosophy (PhD)

Department / School

Plant Science

First Advisor

David E. Clay

Abstract

In the Great Plains wheat yields, dough quality, and protein composition are influences by many factors including genetics, nitrogen (N) and water stress, climate, gluten protein composition, and flour amino acid composition. The objective of this study was to investigate the influence water and N stress and management in selected winter and spring wheat cultivars on grain yield, protein and amino acid composition, and quality. Replicated field research was conducted in selected winter and spring wheat cultivars to determine the impact of N and water stress on yield, yield losses due to stress, protein content and composition, and dough quality. Yield losses due to water stress (YLWS) and yield loss due to N stress (YLNS) were calculated from the grain 613C values. Dough quality was measured with a farinograph and the protein fraction was characterized by size-exclusion-HPLC (SE-HPLC) and reverse-phased-HPLC (RPHPLC). Amino acid composition was quantitatively analyzed with RP-HPLC. Research showed that: 1) soil and climate variability and management can affect yields, protein composition, and dough quality parameters; 2) N and water addition can have synergistic impacts on yields; 3) YLWS and YLNS were negatively correlated to the relative amount of glutenin; 4) YLWS were negatively correlated to grain protein content, dough stability, amino acid composition, and essential amino acid scores; 5) the relative contribution of gliadin to protein decreased from the semi-humid eastern to the central and western portions of the state. These findings suggest that by understanding complex relationships among soil variability, climatic conditions, and genetic variation it should be possible to develop adaptive management practices that increase profitability, and improve overall processing and nutritional quality.

Library of Congress Subject Headings

Wheat -- Genetics
Wheat -- Effects of stress on
Wheat -- Yields
Wheat -- Quality

Publisher

South Dakota State University

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Rights Statement

In Copyright