Abstract
ABSTRACT The objective of this work was to evaluate Fusarium guttiforme inoculation methods and genetic resistance of pineapple accessions. Thus, three experiments were conducted: pathogen inoculation of different leaf types (B, D and F) of pineapple (1), pathogen inoculation of pineapple cuttings and detached D leaves (2), and identification of resistance to fusariosis in 19 pineapple accessions (3) sampled in the State of Mato Grosso, Brazil. The cultivars Pérola (susceptible to fusariosis) and BRS-Vitória (resistant to fusariosis) were used as controls. The fusariosis severity was evaluated at 10, 15, 20, 25 and 30 days after inoculation with F. guttiforme. The lesion diameters (severity level) were used in order to calculate the area under the disease progress curve (AUDPC). The inoculation of detached D leaves was the most efficient, fast and inexpensive method, and the one that most satisfactorily reproduced the disease symptoms. The period of 10 to 20 days after inoculation of the D detached leaves with the pathogen is the most suitable to evaluate the resistance of pineapple accessions to fusariosis. The lowest lesion area and AUDPC was found in the accession 1, in all evaluations. Thus, the accession 1 can be used in pineapple breeding programs for resistance to fusariosis.
Highlights
Pineapple [Ananas comosus (L.) Merril var. comosus Coppens and Leal] belongs to the Bromeliaceae family and is indigenous to South America
Fusariosis is the main disease of pineapple in Brazil, which was reported for the first time in the State of São Paulo by Kimati and Tokeshi (1964)
Silva-Acuña, Costa and Barreto (1995) evaluated C, D and E leaves of the cultivar Pérola inoculated with F. guttiforme by the method of mycelial disk inoculation with injury and found D leaves with larger lesions than the other leaf types, suggesting that this is the most appropriate leaf type to assess the genotype susceptibility to fusariosis
Summary
Pineapple [Ananas comosus (L.) Merril var. comosus Coppens and Leal] belongs to the Bromeliaceae family and is indigenous to South America. Comosus Coppens and Leal] belongs to the Bromeliaceae family and is indigenous to South America. This fruit species of tropical and subtropical climate has great economic and social importance in more than 70 countries (CRESTANI et al, 2010). Brazil is the largest world producer of pineapple, which had a production of 1,762,938 Mg in 2014 (IBGE, 2016). Some factors have hindering the achievement of higher yields of pineapple in Brazil. Fusariosis is the main disease of pineapple in Brazil, which was reported for the first time in the State of São Paulo by Kimati and Tokeshi (1964). Fusariosis is caused by the fungus Fusarium guttiforme (NIREMBERG; O’DONNELL, 1998), which enters host plants through natural openings or injuries in cuttings, fruits, leaves and roots, causing losses of 30 to 40% of fruits and 20% of cuttings (VERZIGNASSI et al, 2009)
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