Resistance of Tomato Fruit (rin and nor Type) to Postharvest Diseases Depends on Stage of Maturity

Abstract

On Sinaloa State, tomato growers test new varieties every year looking high yield, better quality and long shelf life. However, few studies are done to know the resistance to postharvest diseases. The objective was to identify postharvest pathogens that infect this new tomato varieties with characteristics rin, nor or normals (BR84, S211, S69, and S121). Fruits in two stages of maturity (pink and red) were harvested and stored under simulated marketing conditions (20°C and 80% RH). Pathogens found were aisled on PDA and identified under microscope. Different chemicals were tested to control pathogens [NaOCl; Ca(OCl)2; Supersana; iodine; Citrucidal; Captan; and water]. Six fungus species—Alternaria alternata, Fusarium oxysporium, Rhizopus stolonifer, Colletotrichum sp., Rhyzoctonia sp, and Phomopsis sp—were found on all varieties. BR84 fruit (rin type) harvested on pink stage were more resistant than red ones. S69 fruit (nor type) were more susceptible at the pink than at the red stage. S121 fruits (normal type) were equally susceptible at both stages of maturity. Least resistant variety to fungus infection at both stages of maturity was S211 (rin type). Citrucidal and Ca(OCl)2 gave the best control.