In vitro selection of variants for red rot resistance in the subtropical sugarcane cultivar CoJ 64

The present study reported in vitro selection of red rot variants using crude toxin metabolite of fungus Colletotricum falcatum Went causing red rot disease in sugarcane. The embryogenic calli were generated in sugarcane variety CoJ 64 which is high sugar and early maturing but highly susceptible to red rot disease. Three to four months old calli of CoJ 64 were screened in vitro against different concentrations of crude toxin metabolite (5, 10, 15, 20 and 25% v/v PCF) for two selection cycles, each of three weeks duration. Calli survived and exhibited further proliferation at 5, 10, 15 and 20% v/v crude toxin concentrations whereas, at higher concentration (25% v/v) survival and or proliferation was completely inhibited. Shoot regeneration per cent was higher in calli selected on 5%crude toxin concentration than those selected on 10, 15 and 20% concentrations. Crude toxin metabolite of C. falcatum had markedly inhabited on survival and multiplication of sugarcane tissues at all stages viz. survival, proliferation and shoot regeneration of callus. Effect of toxin metabolite on callus survival, proliferation and shoot regeneration was directly related to its concentration in the selection medium.