Effect of foliar applications of phosphite on post

Authors: María C Lobato Milagros F Machinandiarena Cecilia Tambascio Guillermo A A Dosio Daniel O Caldiz Gustavo R Daleo Adriana B Andreu Florencia P Olivieri

Publish Date: 2011/01/29

Volume: 130, Issue: 2, Pages: 155-163

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Abstract

The utilization of phosphites Phi could be considered as another strategy to be included in integrated disease management programmes to reduce the intensive use of fungicides and production costs The aim of the present work was to analyze whether the beneficial effects of phosphite treatment previously observed in potato plants grown under greenhouse conditions were reflected after harvest of field grown potatoes both in disease protection and in yield In addition biochemical compounds possibly involved in induced defence responses by Phi like phytoalexins pathogenesis related proteins and oxidative stress enzymes were measured Foliar applications of KPhi to field grown crops resulted in postharvest tubers with a reduced susceptibility to Phytophthora infestans Fusarium solani and Erwinia carotovora infections suggesting that this compound induced a systemic defence response An increase in phytoalexin content in P infestans inoculated tubers obtained from Phitreated plants suggests their participation in the defence response Chitinase content increased 72 h after wounding or inoculation with P infestans in tubers from KPhitreated plants compared to wounded or infected tubers from nontreated plants Contrary to this the isoforms of β13glucanases analyzed did not increase in the tubers of Phitreated plants The increment in peroxidase and polyphenol oxidase activities indicated that these enzymes could be part of the Phi defence mechanism No negative effects were observed in potato yield at harvest measured as total tuber weight and dry matter after foliar KPhi treatment This suggests that the energetic cost involved in the defence response activation would not be detrimental to plant growthThis work was supported by Consejo Nacional de Investigaciones Científicas y Tecnológicas CONICET Comisión de Investigaciones Científicas de la Provincia de Buenos Aires CIC and Universidad Nacional de Mar del Plata UNMdP McCain Argentina SA and AgroEMCODI SA Machinandiarena MF Dosio GAA Andreu AB and Olivieri FP are established researchers from CONICET Daleo GR is an established researcher of CIC Caldiz DO is Agronomy Manager of the Agronomy Division McCain Argentina SA Lobato MC is fellowship of CONICET and Tambascio C is a fellowship of the Agencia Nacional de Promoción Científica y Tecnología ANPCYT The authors gratefully acknowledge Dr Eugenia Fanjul from Universidad Nacional de Mar del Plata for the statistical assistance

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