Thermal control of some post-harvest rot pathogens of Irish potato (solanum tuberosum l.)

Abstract

Thermal control effect on the incidence of some post-harvest rot pathogens of Solanum tuberosum (potato) was investigated in this study. Three cultivars of potato tuber whose local names are, Patiska, Mai Bawondoya and Nicola were used for the study. Five pathogenic fungi viz: Botryodiplodia theobromae, Fusarium redolens, Fusarium oxysporum, Penicillium sp. and Rhizopus oryzae associated with post harvest storage rot of root-tubers, were isolated from diseased potatoes. Among the three species of potatoes used in the study, Patiska was found most resistant followed by Mai Bawondoya, while Nicola was the least resistant. Increase in substrate (i.e. soluble starch or CMC) concentration enhanced a proportional increase in mycelial growth and in the amount of extracellular enzymes produced. Some of these test pathogens were found to produce cell wall degrading enzymes (i.e. amylase and cellulase). Preferential utilization of carbohydrate sources was established in this study based on the growth of test pathogens. Growth on potato broth medium was highest followed by growth on Cocoyam and Sweet potato broth media and least on Cassava broth medium. Growth of the test pathogens on carbohydrate sources was found at variant. The use of hot water treatment at different temperatures was found to significantly reduce post-harvest fungal populations on the surface of root-tubers. The efficacy of blanching in hot water at 60?C was significantly higher than that of blanching in hot water at other temperatures. The control method adopted in this study showed that the problems of potatoes? rot disease in storage (especially by the peasant farmers) can be eradicated by thermal treatments without reducing the quality of the Irish tuber.U radu je ispitivan uticaj termickog suzbijanja uzrocnika trulezi krtola krompira u skladistu. Ispitivane su tri lokalne sorte krompira: Patiska, Mai Bowondoya i Nicola u Nigeriji. Iz obolelih krtola izolovene su sledece fitopatogene gljive: Botryodiploda theobromae, Fusarium redolens, Fusarium oxysporum, Penicillium spp. i Rhizopus oryzae. Od tri ispitivane sorte krompira Patiska je bila najotpornija na trulez, a zatim Mai Bawondoya, dok je Nicola biola najosetljivija. Pri ispitivanju uticaja izvora ugljenika na porast kolonija, utvrdjeno je da je porast kolonija bio najveci na corbi od krompira, a potom na corbi od Cocoyama i slatkog krompira, a najslabiji na corbi od kasave. Potapanjem krtola 1 Abiodun Olusola Salami ,Plant Science Department, Obafemi Awolowo University, Ile-Ife 2 Abiodun Olusola Salami ,Botany And Microbiology Department, University Of Ibadan, Ibadan kromira u vodu zagrejanu na razlicitim temperaturama znacajno je redukovana populaciju patogena na njihovoj povrsini. Efikasnost tretiranja krtola toplom vodom zagrejanom na 60?C je bila znacajno visa nego pri teretiranju sa toplom vodom zagrejanom na drugim temperaturama. Nacin tretiranja krtola krompira, ispitivan u ovom radu je pokazao da patogeni uzrocnici trulezi uskladistenog krompira (posebno kod seljaka) mogu biti unisteni bez smanjenja kvaliteta krtola krompira.