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Influence of population density on light interception and grain yield involving wheat hybrids

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Title Influence of population density on light interception and grain yield involving wheat hybrids
Names Ganapathy, Mapangada Chengappa (creator)
Kronstad, Warren E. (advisor)
Date Issued 1968-03-08 (iso8601)
Note Graduation date: 1968
Abstract Six wheat hybrids from two sets of parents and their respective
parents were grown at Hyslop Agronomy Farm near Corvallis, Oregon
in the year 1965-66. The object of the experiment was to evaluate the
influence of population densities and different planting patterns on
grain yield and factors which determine grain yield. Factors studied
included the leaf area index, percent light interception, plant height,
and the components of grain yield which are tillers per unit area,
kernel per spike and the weight of 1,000 kernels. The design of the
experiment was first order factorial randomized split plit with 12
phenotypes X two population densities X five patterns of planting.
Leaf area was measured without detaching leaves from the
plant at three stages of growth. These included the jointing stage,
prior to flag leaf and the heading stage. Light interception in the
plant canopy was obtained by exposing ozalid paper which was placed
two inches above the soil surface between the plants for nine hours
during the day, At maturity, data were collected on total dry matter
production, kernels per spike, 1,000 kernel weight and grain yield.
Leaf area index and tillers per unit area in hybrids and parents
were not significantly different at the jointing stage. However, significant
differences were observed for both the characteristics in the
later stages of growth due to the reduction in tiller number per unit
area. The lethal effect on tillers was due to shading of upper leaves
on the same plant and from surrounding plants. Significant differences
among parents and hybrids for tolerance to the influence of shading
was observed. Two hybrids derived from the cross Druchamp X
Redmond and Druchamp X Travero were found to be more tolerant
and produced significantly higher grain yield than their respective
parents.
Leaf area index was found to be influenced by plant density,
patterns of planting, tillers per unit area and plant height. Significantly
higher grain yield was produced with a 12" solid planting than
any other patterns of planting as a result of more tillers per unit
area being present at harvest time.
The percentage light intercepted by the plant canopy was directly
associated with plant height at the jointing stage while in the latter
stages of growth the leaf area index was more important in determining
the amount of light intercepted. Increased population density
per unit area and closer row spacing increased the percentage of
light intercepted. Dry matter production was proportionately higher with increased light interception. The percentage of light intercepted
at the heading stage was found to have a greater influence on grain
yield than at any other stage of growth. The cross Druchamp X
Travero which produced 33 percent higher grain yield than the better
parent was found to exhibit hybrid vigor for all characteristics in the
later stages of growth.
Genre Thesis/Dissertation
Topic Wheat
Identifier http://hdl.handle.net/1957/46757

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