Lines derived from coffee BA-10 with resistance to Pseudomonas syringae under field conditions with simultaneous natural infections of the pathovars garcae and tabaci

Abstract

Bacterial-halo-blight and bacterial-leaf-spot are important coffee diseases caused by Pseudomonas syringae pv. garcae and pv. tabaci, respectively. The most suitable method to control these diseases is the use of resistant cultivars. There are no studies on resistance to Pseudomonas syringae (PS) in coffee derived from BA-10 genotypes. Therefore, the aim of this study was to evaluate the resistance to PS in lines derived from BA-10 under field conditions with simultaneous natural infections of the pathovars garcae and tabaci. 38 F4 and two F5 lines derived from BA-10 were evaluated in a field trial in Londrina, PR, Brazil. The Catuaí Vermelho IAC 81 and IAPAR 59 were the susceptible and intermediate resistant controls, respectively. Resistance to PS was evaluated in January 2017 after 45 months of planting. The grading scale varied from 1 to 5, where grade 1 was plants with more resistance and 5 plants more susceptible. Two F5 lines showed 100% of resistant plants (grades 1 and 2) and the F4 line IAPAR 12201 showed 60% of plants with a high level of resistance to PS (grade 1), while the control Catuaí showed no resistant plant. IAPAR 59 and several F4 lines showed high frequency of plants with intermediate resistance to PS