Abstract

ROJAS-MARTINEZ, Reyna Isabel; ZAVALETA-MEJIA, Emma; NIETO-ANGEL, Daniel  and  ACOSTA-RAMOS, Marcelo. Virulence and Genetic Variation of Isolates of Colletotrichum gloeosporioides (Penz.) Penz. and Sacc. on Mango (Mangifera indica L.) cv. Haden. Rev. mex. fitopatol [online]. 2008, vol.26, n.1, pp.21-26. ISSN 2007-8080.

The virulence and genetic variation shown by RAPD (Random amplified polymorphic DNA) were determined for 15 monoconidial isolates of Colletotrichum gloeosporioides obtained from leaves and fruits of mango (Mangifera indica) cv. Haden. They were classified into four groups according to their degree of virulence onto inoculated leaves: very virulent (from 19.2 to 9.0% severity, isolates F3, F4, and T5), virulent (from 8.0 to 5.0%, T4, T3, F5, and T1), moderately virulent (from 3.8 to 1.2%, H4, H2, T6, F2, and H3), and scarcely virulent (from 0.1 to 0.01%, H1, F1, and T2). F3 was the most virulent as it showed the highest anthracnose severity. Isolates H4, H1, H2, H3, T6, F2, and T2, showed greater genetic variability and were part of a group that was well separated from F3, F4, and F5. These three were outside the main groups in the dendrogram that was constructed from results of the RAPD analysis. T5 (very virulent) was associated with T3 and T4 (virulent); however, F1 (scarcely virulent) was grouped with F5 (virulent). The results from the RAPD analysis suggest the existence of great genetic variability among the 15 isolates of C. gloeosporioides.

Keywords : Anthracnose; RAPD; disease severity.

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