Reação de genótipos de mamoeiro à varíola e à podridão-do-pé

Abstract

Papaya (Caryca papaya) genotypes ('NT Red', 'Golden', 'Baixinho de St. Amália', 'Sunrise Solo', 'Cross Paris', 'Tailândia Verde', 'Tailândia Roxo', 'Tailândia Roxão', 'Sekati' and 'Tainung-1') were evaluated for resistance to black-spot (Asperisporium caricae) and foot-rot (Phytophthora palmivora). The study was conducted in an area where both pathogens occurred naturally and in a greenhouse using soil naturally infested with P. palmivora. Black-spot severity was evaluated using a scale, from 1 (0-3% of the surface covered by lesions) to 6 (> of 50% of the surface covered by lesions). The evaluations were made between March / 2003 and April / 2003 and between October / 2003 and February / 2004. Foot-rot was evaluated, on the field trial, by counting the total number of plants with yellowing or wilt symptoms in the same period. On the greenhouse trials P. palmivora severity was evaluated in each plant using a scale from 0 (no wilt symptoms) to 3 (plant death). In relation to black-spot, the genotype 'Sekati' of the Formosa group presented the lowest average value of severity (2,0) on the foliage while ''Golden' (3,1) and NT Red' (3,7) had the largest. 'Tailândia Roxão' (1,6), 'Tailândia Verde' (1,7) and 'Sekati' (1,7) also had the lowest averages of severity on the fruit, while, 'Tailândia Roxo' (2,3), 'Cross Paris' (2,5), and 'Sunrise Solo' (3,1) presented the largest. In relation to foot rot, 'Tailândia Roxão' (Formosa group) presented low amount of disease and 'Golden', 'Sunrise Solo, and 'NT Red' presented higher values.