http://www.loc.gov/mods/v3 http://www.loc.gov/standards/mods/v3/mods-3-2.xsd
Grain mold resistance in sorghum [Sorghum bicolor (L.) Moench]
genetic, physical and biochemical analysis
xvii, 155 leaves : illustrations ; 28 cm.
Grain mold is the most important problem in terms of grain sorghum utilization. Molded grains have reduced grain quality and market value. Grain infected with mold is also more likely to be contaminated with mycotoxins. The use of cultivates with genetic resistance to this disease offers the only practical and effective means to control grain mold. The objectives of this research were (1) assess inheritance, heritability and stability of grain mold resistance (GMR), (2) examine correlations among GMR and kernel traits, (3) determine the extent of the relationship among grain molding fungi, and (4) evaluate the role of antifungal proteins (AFP's) in grain mold resistance. The inheritance of GMR was studied using generation means analysis of the F₁, F₂ and backcross generations of the cross between Surest and RTx430, grown at 8 environments. Genetic control and heritability was estimated with data from 131 F[] lines, grown at 6 environments. The stability of GMR was evaluated with data from 19 inbred lines sown at 17 environments. Association among grain mold incidence and sorghum kernel traits was determined on caryopsis from individual plants grown at 4 environments. The relationship among molding fungi was estimated on grain samples with different disease incidence levels. The presence of AFP'S was evaluated during grain development of Surely, RTx430 and their F₁, and in grains from 16 F[] derived lines with different GMR. It was found that additive and dominance effects are the most important factors contributing to GMR. Broad and narrow sense heritability were estimated as 0.86 and 0.59 respectively. Genetic advance estimates for GMR ranged from 5-15%. A minimum of 4 genes segregating for GMR was estimated. The environment, genotype and genotype * environment effects have equal importance for GMR. Although kernel traits (seed size, germination, density, test weight and corneous endosperm) are correlated with GMR, they only explained less than 37% of the variability in GMR. It was also found that as grain mold incidence increase so does fungi interaction complexity. Presence of AFP'S in the kernel is associated with GMR.
Issued also on microfiche from University Microfilm Inc.
Includes bibliographical references (leaves 133-143).