Reaction of sweet and hot pepper accesses to powdery mildew (Oidiopsis taurica)

• Autor(es):

  Blat, Sally F. (Universidade de São Paulo. Escola Superior de Agricultura Luiz de Queiroz. Departamento Produção Vegetal);

  Costa, Cyro Paulino da (Universidade de São Paulo. Escola Superior de Agricultura Luiz de Queiroz. Departamento Produção Vegetal);

  Vencovsky, Roland (Universidade de São Paulo. Escola Superior de Agricultura Luiz de Queiroz. Departamento Genética);

  Sala, Fernando Cesar (Universidade de São Paulo. Escola Superior de Agricultura Luiz de Queiroz. Departamento Produção Vegetal).

• Fonte:

  Horticultura Brasileira; volume 23, número 1, páginas 72-75. Março 2005.

• Assuntos:

  Capsicum spp.;

  Leveillula taurica (Lev.) Arn.;

  genetic resistance.

• Resumo:

  Powdery mildew caused by Oidiopsis taurica is one of the major diseases of Capsicum spp., causing damage due to defoliation of up to 75% and yield losses of up to 40%. Disease control with fungicide is inefficient, genetic resistance being the best way of control. Few resistant sources have been identified in Capsicum annuum. Capsicum spp. collection accesses of USP/ESALQ germplasm bank were screened in their reaction and identification of new resistance sources. The screening was carried out in a greenhouse under high inoculum pressure. Disease was assessed during fruit production using a severity scale varying from 1 (resistant) to 5 (highly susceptible). From 156 accesses evaluated 53 were resistant, represented by five accesses in C. annuum, 31 in C. baccatum and 17 in C. chinense. The hv-12 was the most resistant among the C. annuum accesses. Two new resistant sources were found in C. annuum, # 124 and chilli. These accesses showed different resistance mechanisms through hypersensitive host reaction. The commercial hybrids Reinger, Nathalie, Margarita, Magali R and Magda were susceptible or highly susceptible. Most of C. baccatum and C. chinense resistant accesses showed defoliation as a consequence of hypersensitive mechanism.

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