Abstract

A major constraint in the improvement of ‘Egusi’ melon lies in the fact that attempts attransferring desirable genes into the plant from wild relatives are limited by interspecific hybridization barriers. Therefore, antimitotic agents were used as a means of introducing genetic variability for possible incorporation into breeding programmes of the crop. Seeds soaked in water and three different concentrations (0.01, 0.001 and 0.0001 M) of oryzalin and colchicine were planted directly in field plots where data on some quantitative and yield characters were collected. Plants derived from seeds treated with 0.001 and 0.0001 M of both drugs had significantly longer leaves with larger areas, longer internodes and took a fewer number of days to flower with a higher fruit setting percentage than those soaked in 0.01 M and water, respectively. These plants equally produced bigger pod variants that resulted in the production of more seeds, indicating that they were probably polyploids, which was confirmed by flow cytometry. An examination of the plants in subsequent generations indicated that all of these traits were stably integrated and expressed in the mutants, tacitly implying that they were fixed and can be introgressed into traditional varieties through backcrossing for further improvement of ‘Egusi’ melon.

Key words: Antimitotic drugs, colchicine, mutations, oryzalin, pod variants, polyploids.