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作者 Brekke, Brent Howard
書名 Agronomic and phenotypic responses to 75 years of recurrent selection for yield in the Iowa Stiff Stalk synthetic maize population
國際標準書號 9781124149967
book jacket
說明 98 p
附註 Source: Masters Abstracts International, Volume: 49-01, page: 0223
Advisers: Jode W. Edwards; Allen D. Knapp
Thesis (M.S.)--Iowa State University, 2010
The plant density at which Zea mays L. hybrids achieve maximum grain yield has increased throughout the hybrid era while grain yield on a per plant basis has increased little. Changes in plant traits including grain yield, moisture, test weight, stalk and root lodging, flag leaf angle, anthesis-silking interval(ASI), plant height, tassel branch number, and total number of leaves have been well characterized in comparisons of commercial hybrids representing different eras of hybrid maize production but have yet to be examined in a recurrent selection program
The objective of this experiment was to determine if direct selection for grain yield and agronomic performance in the Iowa Stiff Stalk synthetic population has indirectly improved adaptation to high plant density. Material from an unselected base population, Iowa Stiff Stalk Synthetic (BSSS), was compared to the most advanced cycles of selection from two different recurrent selection programs at seven Iowa locations in 2008 and 2009
Populations were compared at densities of 38,300, 57,400, 77,500, and 95,700 plants ha-1. Treatments were replicated twice at each location and arranged in a split plot design. Increasing density in advanced populations led to increased yield unlike the yield decrease seen in less advanced populations at high density, indicating an adaptation to high plant density. Increasing density in advanced populations did not increase grain moisture, test weight, or stalk lodging supporting our hypothesis of increased adaptation to high plant density in more advanced populations. Root lodging has remained unchanged
Advanced populations had reduced ASI. Plant density did not affect flag leaf angle which became more vertical in advanced populations. Increasing plant density in advanced populations increased plant height while not effecting ASI or tassel branch number; supporting our hypothesis of increased adaptation to high plant density
School code: 0097
Host Item Masters Abstracts International 49-01
主題 Agriculture, Agronomy
Biology, Plant Physiology
0285
0817
Alt Author Iowa State University. Agronomy
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