Genotypes of conilon coffee and their reaction to coffee leaf rust

ABSTRACT The objective of this study was to evaluate the behavior of 54 conilon coffee clones from the Incaper Genetic Improvement Program to rust under controlled conditions of temperature and photoperiod. A completely randomized design with three replicates was used, and each replicate was composed of 16 leaf disks each, which were packed in gerboxes and inoculated with 104 spores.mL-1 H. vastatrix. The gerboxes were stored in the absence of light at 22ºC for 48 hours and subsequently at 12-hour photoperiod until the end of the experiment. The evaluated resistance components were: incubation period, latent period, incidence, percentage of disks with sporulation, number of spores and severity. Based on the results, three groups of conilon coffee genotypes were identified: Resistant, Moderately Resistant and Susceptible. To the Resistant group, 19 genotypes were allocated; to the Moderately Resistant group, 19 genotypes were allocated and to the Susceptible group 16 susceptible genotypes were allocated. Thus, results led to the conclusion that there is a variation in the resistance level of C. canephora genotypes to H. vastatrix. Such information subsidizes breeding programs in properly selecting C. canephora progenies for resistance to rust.