Differential response of pepper ( Capsicum annuum L.) lines to Phytophthora capsici and root-knot nematodes

The oomycete P. capsici is among the major pathogens found in pepper. A desirable, sustainable and environmentally-compatible way to manage it is through genetic resistance. Huacle and Serrano pepper lines resistant to P. capsici isolate 6143 have been detected; however, it is necessary to determine whether the resistance of these lines is effective against a higher number of isolates and evaluate their resistance to other important pathogens, such as root-knot nematodes. The aim of this study was to evaluate the resistance of Huacle and Serrano pepper lines to different P. capsici isolates and root-knot nematodes (M. incognita and N. aberrans). Ten P. capsici isolates from different pepper-growing regions, and two independently-inoculated nematode populations, one of M. incognita and the other of N. aberrans, were used. Serrano pepper, lines 41-1, 41-2, 42-6 and 55-2 stood out, with a resistance response to all P. capsici isolates followed by Huacle pepper lines 33-3, 35-3 and 34-3, which were only susceptible to one isolate. Furthermore, except for lines 34-3, 35-5 and 42-2, all the others were resistant to M. incognita. Serrano pepper lines 41-1, 41-2 and 42-2 and Huacle lines 35-3 and 35-5 were resistant to N. aberrans, while lines 41-1, 41-2 and 35-3 lines were resistant to the three pathogens evaluated. Resistance previously detected in Huacle and Serrano peppers is effective for different P. capsici isolates and root-knot nematodes.