Thesis (Ph. D.)--University of Missouri-Columbia, 2001. / Typescript. Vita. Includes bibliographical references (leaves 143-149). Also available on the Internet.

Thesis (Ph. D.)--University of Missouri-Columbia, 2001. / Typescript. Vita. Includes bibliographical references (leaves 117-121). Also available on the Internet.

Thesis (Ph. D.)--University of Missouri-Columbia, 2001. / Typescript. Vita. Includes bibliographical references (leaves 143-149). Also available on the Internet.

Thesis (Ph. D.)(Plant Production)--University of Pretoria, 2001. / Includes bibliographical references).

Data were collected on 24 traits to characterize and classify 35 white floury corn (Zea mays L.) landraces collected on native reserves in Ontario. Several landrace x landrace and landrace x inbred crosses were evaluated. Test crosses were made to determine whether the landraces carry the floury-l (fl$ sb1$) allele. Most traits examined exhibited considerable variation among the landraces. Variation was also observed within many of the landraces for ear and cob colour, for endosperm texture and row number. The landraces were grouped into 10 clusters by centroid clustering analysis. Significant heterosis over the mid-parent value was observed in the crosses among landraces. Some crosses between landraces and inbreds yielded more than either parent. Crossing the landraces with the inbreds improved some agronomic characteristics, but disrupted some of the ear characteristics of the landraces. The floury factor responsible for the characteristic endosperm texture of the IAPO landraces was identified as being the dosage dependent fl$ sb1$.

Studies of corn root morphology, canopy description, light and nutrient relationships, have focused on conventional corn hybrids. We are now extending these studies to other corn types with contrasting canopy and root architectures. Field and greenhouse experiments were carried out in order to characterize root morphology, N status in the plant and its relationship with yield and yield components, canopy architecture and light interception of these genotypes. The indoor experiments investigated root morphology and how N affects it. Root fractal geometry and its relationship with standard measured root variables were investigated. The field research, at two sites and over two growing seasons, examined (i) maize canopy architecture with regard to light interception and (ii) nitrogen effects on grain yield of different maize genotypes. Four genotypic types were included: (i) Leafy reduced-stature, Lfy1rd1 (LRS), (ii) non Leafy-reduced stature, lfyrd1 (NLRS), (iii) Leafy normal stature, Lfy1Rd1 (LNS), and (iv) conventional commercial hybrids, lfy1Rd1. Pioneer 3905 served as the check hybrid for late maturity, and Pioneer 3979, the check for early maturity. The work allowed development of following methods: (i) root sampling for measurement of large root systems, (ii) staining to enhance root contrast for measurement with a scanner-based software system, (iii) sample size determination for SPAD meter readings, and (iv) the design and construction of a mobile and multi-strata device for measurement of light interception. Data were collected for mathematical characterization of canopies (i.e. leaf angle, co-ordinates of the maximum height of the leaf, co-ordinates of the leaf tip), plant N status (SPAD meter readings), light interception, yield and grain yield components. Conventional hybrids generally showed greater root length and surface area than their leafy genotypic counterparts at early developmental stages (i.e. up to 15 days from emergence). However, Leafy geno

An experiment was conducted to investigate the effects of N formulation, application rate, and application time on corn yield and quality under Eastern Canadian conditions, to evaluate the hypothesis that application of N will increase corn grain yield and protein concentration without decreasing the total energy content. Three N formulations, each with the rates of 90, or 180 kg ha$ sp{-1}$ were applied at different times. The results indicated that the grain yield increased with increasing N fertilizer rate and with increasing numbers of N application times. N application significantly increased grain protein concentration, on both a per kernel and a dry matter basis, and protein yield. Such as, N application increased the averaged protein concentration, on a dry matter basis, of corn grain by about 8.40% as compared to the control. The protein concentration was not affected by the number of N application times before the plants were 90 cm high. Neither lipid nor non-structural carbohydrate concentration, on both a per kernel and a dry matter basis, were significantly affected by N application in most of the location-years. In addition Near infrared reflectance (NIR) was used to determine the lipid concentration in the aerial corn tissue at different growth stages. The correlation coefficients between the standard analytical method and the NIR method of lipid concentration were all above 0.95, and were significant at 0.01 level.

Thesis (Ph. D.)--University of Hawaii at Manoa, 1995. / Includes bibliographical references (leaves 228-240). / Microfiche. / xx, 240 leaves, bound ill. (some col.) 29 cm

Thesis (Ph.D.)--University of Missouri-Columbia, 2006. / The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on May 1, 2009) Vita. Includes bibliographical references.

Thesis (Ph. D.)--University of Missouri-Columbia, 1997. / Typescript. Vita. Includes bibliographical references. Also available on the Internet.