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Combining ability for resistance to powdery-mildew in papaya

Genetic resistance represents a sustainable alternative to control powdery-mildew in papaya crop. Diallelic crosses were performed among eight papaya genotypes, belonging to 'Solo' and 'Formosa' heterotic groups, four from each one with aiming to indicate possible hybrid combinations that contribute to reducing the severity of powdery-mildew on leaf. The 56 hybrid combinations (F1's and reciprocals) along with their parents were evaluated in a randomized complete block design with four replications. Powdery-mildew severity on leaves was measured in March and May 2010, respectively, at 11 and 13 months after planting. The general and specific combining ability were estimated from the severity data. Thus, considering the estimates of combining ability, the hybrids 'Maradol x Waimanalo', 'Maradol x Sunrise Solo 72/12', 'JS 12-4 x São Mateus', 'Sekati x Waimanalo', 'Sekati x Golden', 'Sekati x Sunrise Solo 72/12', 'Sekati x São Mateus', 'Waimanalo x São Mateus' e 'Golden x São Mateus' are the best combinations for the parents assessed to the severity of powdery-mildew. The results also show the possibility of obtaining hybrids with potential for reducing the severity of powdery-mildew, from crosses between genotypes of the groups 'Solo' and 'Formosa' and at crossings within the 'Solo' group.

Streptopodium caricae; Carica papaya; hybridazation


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