Increase of the resistance to late blight by biocompatible compounds

LOBATO, C.; OLIVIERI, F. P.; DALEO, G. R.; ADRIANA BALBINA ANDREU

Pinamar. Argentina

Congreso; SAIB 41th Annual Meeting; 2005

Sociedad Argentina de Investigación en Bioquímica y Biología Molecular

In Argentina, more than 80% of the cultivated potato varieties are susceptible to late blight. This means that most potato agroecosystems are dominated by large patches of genetically homogeneous crop, which favored rapid development of the disease. Therefore, large amounts of fungicides are needed to control it, resulting in high costs of production, environmental contamination and the risk of developing pathogen resistance. All these factors have emphasized the need for an alternative chemical for integrated crop management. Phosphites, differing in its mode of action from fungicides, could be such an alternative. Hence, the present study was to determine the effect of Potassium and Calcium Phosphite (KPhi and CaPhi) on the control of late blight. Plants of cvs. Shepody and Kennebec (grown under greenhouse conditions), were sprayed with doses of 2 lt/ha of KPhi and CaPhi or water, six weeks after emergence. Five, eleven, fourteen and twenty days after these treatments, leaves were cut and inoculated with P. infestans. At the first time (5 days after treatment), the leaves were processed for biochemical analysis. The expression and activity of basic chitinases and β1-3 glucanases were increased by CaPhi treatment in both cultivars, but only in cv. Kennebec with KPh. High level of protection against P. infestans was observed until fourteen days of treatment with KPhi in both cultivars and lower with CaPhi. These protections decreased at 20 days after treatment. It is also necessary to evaluate the application times and rates for the control of potato tuber infections.