Off-campus UNL users: To download campus access dissertations, please use the following link to log into our proxy server with your NU ID and password. When you are done browsing please remember to return to this page and log out.
Non-UNL users: Please talk to your librarian about requesting this dissertation through interlibrary loan.
SELECTION FOR GRAIN YIELD UNDER WATER STRESS IN SORGHUM (SORGHUM BICOLOR (L.) MOENCH) (SUSCEPTIBILITY INDEX, ADJUSTED RESIDUAL, AUGMENTED DESIGN)
Abstract
Three different experiments, involving two different sources of sorghum genetic material, were designed to evaluate the use of a simple stress/nonstress screening technique to select for improved performance under water stress conditions. In the first two experiments, S(,3) families selected from the top yielding S(,2) family rows of the Texas population, TP2, under irrigation and dryland environments in 1983, were evaluated under stress and irrigated environments at Garden City, Kansas and Mead, Nebraska. The 160 S(,3) families at each water level were arranged in an augmented black design with 5 checks replicated 8 times. Experiment 3 involved S(,5) familes extracted from Nebraska population NP3R at Sidney, Nebraska and were evaluated in an augmented design with 5 checks under both dryland and irrigation at Mead, Nebraska. Water stress, in all three experiments, significantly affected plant growth, grain yield and yield components. Time to 50% bloom was not affected by the stress. In the two experiments involving the Texas population, the genotypic response to stress in terms of yield and yield components was significantly related to the time to 50% bloom at both locations. Most of the variation in yield response to stress was removed when yield was adjusted to time to 50% bloom. The two locations differed significantly in the timing and intensity of stress. The genotypes responded differently to the two types of stress, indicating that the repeatability of response was conditioned by the repeatability of the timing and intensity of stress. In both genetic materials, selections based on absolute yield under either stress or nonstress environments did not result in yield superiority in either environment or in improved response to stress. Grain yield under stress was closely related to nonstress yield (yield potential). Attempts to separate yield response to stress from yield potential by using either the susceptibility index method or the adjusted residuals obtained from regressing stress yield on nonstress yield, were successful, and could be used in selecting genotypes with superior performances under stress independent of their yield potentials.
Subject Area
Agronomy
Recommended Citation
ABDELRAHMAN, MOHAMED ELKHEIR, "SELECTION FOR GRAIN YIELD UNDER WATER STRESS IN SORGHUM (SORGHUM BICOLOR (L.) MOENCH) (SUSCEPTIBILITY INDEX, ADJUSTED RESIDUAL, AUGMENTED DESIGN)" (1985). ETD collection for University of Nebraska-Lincoln. AAI8526610.
https://digitalcommons.unl.edu/dissertations/AAI8526610