Evaluation of the Reaction of Various Potato ( Solanum tuberosum L.) Cultivars to the Meloidogyne incognita and Ralstonia solanacearum Disease Complex under Field Conditions

The performance of various potato cultivars in response to disease pressures from Meloidogyne incognita (MI) and Ralstonia solanacearum (RS) is believed to be different. The experiment was laid out in a randomised complete block design (RCBD) with three replications. A total of 13 potato cultivars during the main cropping season were assessed. The mean squares values from the analyses of variance for MI, RS, and plant parameters of potato cultivars at the two hot spot sites, ‘ Kersa ’ and ‘ Arbarakate ’ for the two pathogens showed highly significant ( P < 0.01) differences among cultivars in terms of response to pathogens and plant parameters. At ‘ Kersa ’, all of the tested potato cultivars were classed as ‘moderately resistant’. However, ‘ Gudenie ’ and ‘ Belete ’ were classed as ‘resistant’ to RS. At ‘ Arbarakate ’, ‘ Belete ’, and ‘ Bubu ’ were classed as ‘resistant’ to MI, while ‘ Gudenie ’, ‘ Belete ’, and ‘ Bubu ’ were classed as ‘resistant’ to RS. At ‘ Kersa ’, ‘ Gudenie ’ recorded the highest mean values (25.5 t ha −1 ) of marketable tuber yield (MY) and total yield (TY) (39.2 t ha −1 ). At ‘ Arbarakate ’, the highest mean value (49.6 t ha −1 ) of TY was registered from the cultivar ‘ Bubu ’. TY had a negative phenotypic correlation with the pathogen’s parameters but a positive with plant parameters. ‘ Gera ’ was the most distant from all tested cultivars with Euclidean distance = 30.8. These assessments provide information for breeders for further improvement through selection.