Abstract

Papaya cultivation has great economic importance in tropical and subtropical countries, and Brazil is one of the largest producers of papaya (Carica papaya L.) in the world. However, productivity is hampered by plant health problems, particularly the pathogen Colletotrichum spp., which causes anthracnose and great damages on postharvest handling. This study characterized the morphocultural and genetic diversity of 21 isolates of papaya Colletotrichum spp. from different Brazilian states. The species were identified using the taxon-specific primers for Colletotrichum gloeosporioides and Colletotrichum acutatum. Eleven ISSR molecular markers were used to investigate the genetic diversity of the isolates. Moreover, the mycelial growth rate, pathogenicity, average diameter and colony color parameters were used in the morphocultural characterization. Of the 21 isolates, 19 were identified as C. gloeosporioides and two as C. acutatum. The ISSR markers showed great genetic diversity between the C. gloeosporioides and C. acutatum isolates, especially those from different locations. The morphocultural aspects displayed high polymorphism, and Linhares-1 and Linhares-2 isolated stood out for having unique characteristics when compared to other isolates. The pathogenicity test was positive for all isolates, but with different severity degree. C. gloeosporioides and C. acutatum displayed high genetic diversity among the isolates from different locations, and great morphocultural variability among isolates of papaya Colletotrichum.

Key words: Inter simple sequence repeat, Carica papaya L. Colletotrichum acutatum, Colletotrichum gloeosporioides.