Cultivares de tomateiro em diferentes epocas de plantio no perimetro irrigado de Sao Goncalo.

Visando obter informações sobre as melhores épocas de plantio e verificar o comportamento de quatro cultivares de tomateiro (Lycopersicon esculentum L.) - Rossol, IPA 1, IPA 2 e IPA 3 -, foram instalados ensaios em solos aluviais da estação experimental do perímetro irrigado de São Gonçalo, em Souza, PB. Os trabalhos de campo foram iniciados em janeiro de 1981 e concluidos em maio de 1982. A cada mês era instalado um enaio. Foram avaliadas, em cada cultivar, nas diferentes épocas de plantio, as seguintes características: produtividade, incidência de podridão estilar, peso médio de frutos e incidência de pragas e doenças. Não houve diferença de produção entre as cultivares, dentro das diferentes épocas de plantio. As melhores épocas de plantio para a região foram os meses de fevereiro, março, abril e maio- As menores produções obtidas foram as dos plantios realizados nos meses de setembro, outubro, novembro, dezembro e janeiro.

Natural parasitism of lepidopteran eggs by Trichogramma species (Hymenoptera: Trichogrammatidae) in agricultural crops in Minas Gerais, Brazil.

The genus Trichogramma Westwood (Hymenoptera: Trichogrammatidae) includes insect egg parasitoids that are widely used throughout the world as control agents of pest insects. The aim of this study was to identify the species of Trichogramma naturally associated with the eggs of lepidopteran pests of the following agricultural and horticultural crops: collards, Brassica oleracea L. (Brassicales: Brassicaceae); papaya, Carica papaya L. (Capparales: Caricaceae); tomato, Lycopersicon esculentum Mill. (Solanales: Solanaceae); cassava, Manihot esculenta Crantz (Malpighiales: Euphorbiaceae); banana, Musa sp. L. (Zingiberales: Musaceae); passion fruit, Passiflora sp. Degener (Malpighiales: Passifloraceae); sugarcane, Saccharum sp. L. (Poales: Poaceae); and corn (maize), Zea mays L. (Poales: Poaceae); and an invasive species (Sodom?s apple milkweed, Calotropis procera Aiton; Gentianales: Apocynaceae) in the semiarid region of Minas Gerais, Brazil. We report natural parasitism by Trichogramma in eggs of Agraulis vanillae vanillae (L.) (Lepidoptera: Nymphalidae), Antichloris eriphia F. (Lepidoptera: Arctiidae), Danaus sp. (L.) (Lepidoptera: Nymphalidae), Diatraea saccharalis F. (Lepidoptera: Crambidae), Erinnyis ello L. (Lepidopera: Sphingidae), and Protambulyx strigilis L. (Lepidopera: Sphingidae). In total, 2,242 specimens of Trichogramma were obtained, belonging to the species T. pretiosum Riley, T. manicobai Brun, Moraes & Soares, T. marandobai Brun, Moraes & Soares, and T. galloi Zucchi. These species of Trichogramma may be candidates for biological control programs of lepidopteran pests in the semiarid region of Minas Gerais and in other semiarid regions.

Banco ativo de germoplasma de tomate mantido na Embrapa Hortaliças.

O presente trabalho teve como objetivo relatar as principais atividades realizadas no BAG tomate (enriquecimento, multiplicação, caracterização e conservação) e sua aplicação dentro dos programas de melhoramento genético.

The mitochondrial elongation factor LeEF-Tsmt is regulated during tomato fruit ripening and upon wounding and ethylene treatment.

A gene encoding an elongation factor LeEF-Tsmt that participates in the protein synthesis process in mitochondria shows strong expression in ripening fruit as compared to other organs. It is strongly up-regulated during the first stages of the ripening process in parallel with the climacteric rise in respiration. LeEF-Tsmt expression is stimulated by ethylene, wounding and high temperature but ethylene-insensitive mutants exhibit normal expression. Transgenic fruit have been generated in which LeEF-Tsmt has been constitutively up- and down-regulated. Surprisingly, altering the expression of the gene by genetic transformation with antisense and sense LeEF-Tsmt constructs did not affect the pattern of respiration and ethylene production during ripening and upon wounding. In addition, expression of the alternative oxidase gene which is known to play an important role in respiratory climacteric was not affected. Possible reasons for the absence of effect on respiration of variations of LeEF-Tsmt gene expression are discussed.