Fusarium guttiforme Inoculation Methods for Resistance Phenotyping in a Segregating Pineapple Population

Pineapple (Ananas comosus (L.) Merr.) is an economically important crop in Brazil, but its production is constrained by fusariosis caused by Fusarium guttiforme. This study evaluated two inoculation and resistance-phenotyping procedures in a segregating population derived from a cross between the susceptible cultivar 'Pérola' and the resistant cultivar 'BRS Imperial'. The experiment was conducted using an augmented block design with 73 hybrids and the two parents as common checks. Plants were evaluated using detached-leaf and direct stem inoculation procedures, and lesion area was quantified using ImageJ. Significant genotypic effects were detected for all evaluated traits (p < 0.01). Stem lesion area showed a higher coefficient of determination of genotypic effects (h²g = 0.67) than the leaf traits (h²g = 0.31), indicating greater discrimination among segregating individuals under the evaluated conditions. Maximum leaf lesion area and leaf AUDPC were strongly correlated (ρ = 0.954), whereas neither leaf trait was significantly associated with stem lesion area. IBP2_70, IBP2_24, and IBP1_3 showed adjusted genotypic values lower than that of the resistant cultivar 'BRS Imperial' and were identified as promising candidates for subsequent validation. These results show that both procedures detect genotypic variation but provide non-equivalent phenotypic information.