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.
GENETIC VARIABILITY AND THE INHERITANCE OF ALUMINUM TOLERANCE IN MAIZE (ZEA MAYS L.)
Abstract
Maize genotypes were grown in nutrient solutions with different levels of Al and P to study genetic variability and the inheritance of Al tolerance. Brazilian inbred lines evaluated on acid soils of that country were substantially more tolerant than American lines when grown in nutrient solutions with added Al. Responses of inbred lines to Al levels were found to be affected by the P level in the nutrient solution. The inheritance of Al tolerance was studied in nutrient solutions with 185 (mu)M Al and 45 (mu)M P. Root lengths of generations (P(,1), P(,2), F(,1), F(,2), BC(,1) and BC(,2)) derived from crosses between tolerant and nontolerant inbred lines showed that additive gene effects explained most of the genetic variation for Al tolerance. Dominance effects accounted for about half as much variation as did additive effects. Epistasis effects were small compared to the others. The frequency distributions of plants within the F(,2) generations were found to be continuous, unimodal and typical for a quantitatively inherited trait, with a general tendency for nontolerance to be dominant over tolerance. In a diallel cross among inbred lines, the analysis of F(,1) crosses indicated that the variance for general combining ability explained most of the variation, but specific combining ability was always statistically significant. The original Brazilian population "Composto Amplo" and the fourth cycle of selection for grain yield in an acid soil of that country were compared at different Al levels in nutrient solution. Root lengths of the original population were longer at low and shorter at high Al levels when compared with the selected population. However, the selection in acid soil decreased the frequency of the most Al tolerant plants. When both "Composto Amplo" populations were compared with temperate and temperate x tropical populations they were found to have high frequency of genes for tolerance. Energy dispersive x-ray fluorescence analyses for mineral element concentrations and contents in tops and roots of maize populations were made. Except for low Cu concentration in roots, the mineral elements determinations were not related to Al tolerant genotypes.
Subject Area
Agronomy
Recommended Citation
MAGNAVACA, RICARDO, "GENETIC VARIABILITY AND THE INHERITANCE OF ALUMINUM TOLERANCE IN MAIZE (ZEA MAYS L.)" (1982). ETD collection for University of Nebraska-Lincoln. AAI8228152.
https://digitalcommons.unl.edu/dissertations/AAI8228152