Date of Award


Document Type


Degree Name

Doctor of Philosophy (PhD)


Plant, Environmental Management and Soil Sciences

First Advisor

Gerald O. Myers


The most influential cultivars from 16 cotton breeding programs were identified based on the analysis of the pedigree of 260 cultivars released between 1970 to 1990. A diallel cross containing ten parents and 45 F 1s (no reciprocals) was conducted to investigate general (GCA) and specific (SCA) combining ability for yield, yield components, and fiber properties of ten influential cultivars. The ten cultivars varied significantly for all the traits except for seed cotton yield and fiber length uniformity. Significant or highly significant GCA effects were detected for 11 of 12 traits studied. This indicates important additive gene action for the majority of the traits investigated among the ten cultivars. Lint percentage, boll weight, lint index, seed index, and fiber length also showed significant SCA effects, suggesting that non-additive gene action was involved in the inheritance of these traits. GCA effects were generally more important than SCA effects. Correlation analysis revealed many positive or negative relationships among the GCA effects for yield, yield components, and fiber properties. Environments were found to have a great influence on yield, yield components, and fiber properties. Random amplified polymorphic DNA (RAPD) analyses were performed to evaluate DNA variation of the ten influential cultivars. Of eighty-six random decamer pruners screened for their capability of amplifying DNA via the polymerase chain reaction (PCR), 63 primers generated a total of 312 fragments. Forty-two bands were polymorphic, which showed a low percentage (13.5%) of DNA variation among the cultivars. All cultivars could be differentiated by nine primers. A cluster was created based on genetic distance calculated from RAPD data.