Effects of the time and temperature of storage bean grains Phaseolus vulgaris L. on the expression of the resistance to the bean weevil Acanthoscelides obtectus (Say, 1831) (Coleoptera: Bruchidae).

Author(s)

Edson Luiz Lopes Baldin

• Document type: Doctoral Thesis
• Press: Ribeirão Preto.
• Institution: Universidade de São Paulo (USP). Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto (PCARP/BC)
• Defense date: 2001-11-01

Examining board members

Fernando Mesquita Lara; Valter Arthur; Arlindo Leal Boiça Junior; Alcebiades Ribeiro Campos; Jose Djair Vendramim

• Advisor: Fernando Mesquita Lara

Abstract

Aiming to evaluate the effects of the time and temperatures of storage bean grains Phaseolus vulgaris L. on the expression of the resistance to the bean weevil Acanthoscelides obtectus (Say, 1831), free and no choice tests were accomplished under laboratory conditions. The preference for oviposition and damages caused by the weevil in pods and grains were evaluated under greenhouse conditions. The genotypes used in the assays were Arc.1S, Arc.3S, Arc.5S, Carioca Pitoco, Ipa 6, Porrillo 70, Onix, Arc.1, Arc.2, Arc.3 and Arc.4. In free choice test using grains of different ages, the wild genotypes Arc.1S and Arc.5S expressed antibiosis and/or no-preference for feeding as resistance mechanisms to A. obtectus; the genotypes Arc.1 and Arc.2 presented only antibiosis; Arc.3S expressed no-preference for oviposition and low antibiosis levels. In no-choice test, the genotypes Arc.1S, Arc.3S, Arc.5S, Arc.1 and Arc.2 expressed antibiosis. In test where the influence of the size of grains was evaluated in the expression of resistance, the wild genotypes Arc.1S, Arc.3S and Arc.5S expressed antibiosis and/or no-preference for feeding; Arc.1 and Arc.2 expressed antibiosis. In the study with grains stored under different temperatures, antibiosis was observed in grains of Arc.1S and Arc.2, independently of the confinement temperature; in Arc.1, it was observed that the antibiotic effects of its grains were reduced as the storage temperature increased. It was also verified that 25°C was not the best temperature to discriminate genotypes in studies of resistance, comparatively to 20°C and 30°C. In greenhouse the pods and grains of Arc.4 were the most preferred for oviposition and feeding by A. obtectus, comparing to the other materials; Arc.1, Arc.5S, Ipa 6, Arc.3S and Porrillo 70 were the least preferred for oviposition and feeding by the bean weevil. (AU)