ENVIRONMENTAL EFFECTS ON THE DIFFERENTIATION OF ABNORMAL COTTON FLOWERS

Previous studies have shown that both genes and cytoplasm have important effects on the number of anthers and external ovules borne by the staminal columns of flowers on plants with the EO gene. Under Mississippi Delta conditions a single plant may produce flowers daily for three months or more. The basic premise for the study reported here was that each of these 100-200 flowers of a single plant exposed a constant gene-cytoplasm combination to an extremely variable environment. Highly significant correlations with environment were found as follows: Number of anthers with relative humidity 22 days before anthesis, number of external ovules with minimum temperature 19 days before anthesis, and percentage of sterile anthers with maximum temperature 15-16 days before anthesis. The external ovule property thus permits study of flower differentiation by manipulating three different variables: (1) cytoplasm, (2) gene dosage, and (3) environment.