Effects of highly concentrated KCl foliar spray for managing the occurrence of the internal brown spot, a physiological disorder of potato tubers

Abstract

ABSTRACT Potato (Solanum tuberosum L.) under Mediterranean climate may be affected by internal brown spot, non-pathogenic disorder of flesh tissues leading to a dramatic depreciation of tubers. Its aetiology is still clarifying; however, some abiotic stressors, such as the high temperatures, heat and drought are noticed as crucial factors exacerbating the physiological decline. With the aim of escaping the potato growth stages most prone to the physiopathy, shortening cropping cycle by KCl-induced potato canopy desiccation was experimented on two field trials. Experimental field treatments were two consecutive KCl foliar applications, respectively at thirty and twenty days before harvesting, at 113 and 75 g L−1, that were compared to the water-sprayed control. Salt solution spraying injured above-ground parts ending potato’s growth early reducing incidence of tuber internal browning, on average, between 30% and 50% at low and high KCl concentration, respectively. The non-sensitive cultivar Agria proved the most productive, whereas Ricciona di Napoli resulted strongly defected by the physiopathy. Under low-irrigation regime, IBS occurrence was reduced of about 39%. The reduction of the transpiration flow and growth cycle likely decreased internal brown spot under KCl vine desiccation, as well as the role of KCl on tuber ripening dynamics cannot be overlooked.