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|Title:||Genetic and Environmental Responses of Harvest Index and Other Agronomic Traits in Winter Wheat (Triticum Aestivum L.) and Spring Oats (Avena Sativa L.)|
|Author(s):||Howey, Arden Eugene|
|Department / Program:||Agronomy|
|Degree Granting Institution:||University of Illinois at Urbana-Champaign|
|Abstract:||Two experiments conducted with winter wheat and spring oats investigated the potential of several agronomic traits, especially harvest index, total dry matter production, and growth rate, for improving grain yield. The effect of four nitrogen fertilizer treatments on harvest index, grain yield, grain protein percentage, grain protein yield, and total dry matter yield of wheat was evaluated for nine soft and three hard red winter wheat cultivars in 1979 and 1980. Nitrogen harvest index, straw protein percentage, and the total, reduced, and nitrate nitrogen concentrations of the foliage at anthesis were also examined. Application of supplemental nitrogen increased grain, grain protein, and dry matter yields in 1980 but had no positive effect in 1979 due to a severe drought condition. Nitrogen harvest index and harvest index were not increased in either year by supplemental nitrogen while increases for straw and grain protein percentage, and for the three anthesis nitrogen concentrations were found in both years. Responses of individual cultivars to individual nitrogen treatments were inconsistent due to a sharp year x nitrogen treatment interaction.
Soft wheat cultivar, 'Roland', had the highest harvest index, grain yield, and grain protein yield but was low for grain protein percentage. Grain yield, harvest index, nitrogen harvest index, and anthesis nitrogen concentrations were low for the hard wheat cultivar, Lancota, while grain protein percentage was high. Dry matter yields were similar among cultivars despite grain yield differences.
Improvement of oat grain yields by selection of harvest index, dry matter yield, or growth rate was evaluated in 1979 and 1980. Droughty conditions in 1979 limited progress from selection, however, a 4.8% advance in mean F(,4) grain yield was realized for the oat cross 'Lang x Il. 75-1056' using dry matter yield and a restriction on maturity in selection among F(,3) lines. Observed gains using this scheme were 5.6, 3.9, and 8.9% for the oat crosses 'Il. 72-5514 x Wright', 'Noble x Wright', and 'Lang x Il. 75-1056', respectively, when selection was among F(,3) lines grown in 1980. Selection of harvest index or of growth rate did not result in significant grain yield gains for the populations studied.
Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1982.
|Date Available in IDEALS:||2014-12-16|