Pages: (1-7 )
Abstract
The mutation effects of different concentrations of colchicine (0.1 to 1.0%) on the morphology and cytology of Solanum macrocarpon were investigated. The four established mutant lines (M1, M2, M3 & M4) showed consistent variability from the natural species. Delayed germination (3-6 days) and death of embryos were observed in several treated seeds. Some radicles exhibited tumourous swellings and altered geotropic response by forming loops or rings at the tip. Cotyledons were two in M3 and M4 as in the natural species but three in M1 and M2. Leaves of mutants were generally smaller and slightly folding while the shoots were procumbent and prostrate (M1 & M2), with short and sparse internodes. Epidermal cells were irregular in shape in M3 while stomata with one guard cell were common in M1 and M4. Flowering was inhibited in M2 and fertility lowered in M1, M3 and M4. Fruits were smaller and contained fewer seeds in the mutant plants. The M1, M3 and M4 were regular diploids (2n =24) like the natural species while chromosomes doubled in the M2 producing an autotetraploid (2n = 48) with relatively stable genome.
Keywords: Mutagenesis, mutants, Solanum macrocarpon, autotetraploid, colchicine,