RESUMO
There is a need to implement a new approach to pest control in which agroecological strategies are developed and adapted in a site-specific way to highly variable and diverse farm conditions typical of farms in tropical regions such as Brazil. It has become evident that the conventional agriculture based on high use of external inputs and oriented to maximize profits, has often been detrimental and unviable when considered from social and ecological perspectives. Pest problems, for example, are generally related to high input, single-crop agroecosystems. We discuss here agroecological strategies such as conservation biological control, use of natural pesticides and selectivity of synthetic and natural pesticides as a way to conserve and increase natural enemies' efficiency in Brazilian agroecosystems. In addition, we discuss some patents related to agroecological pest management.
Assuntos
Agricultura/métodos , Artrópodes , Patentes como Assunto , Controle de Pragas/métodos , Praguicidas , Animais , Brasil , Conservação dos Recursos Naturais , Controle Biológico de Vetores/métodosRESUMO
The inheritance of the tendency to set parthenocarpic fruit in the summer squash (Cucurbita pepo L.) line Whitaker was studied. Two parental lines, Whitaker (parthenocarpic) and Caserta (non-parthenocarpic), and the F1 and F2 generations and backcrosses to both parents were tested. The parthenocarpic tendency of individual plants was scored on a scale from 1 (non-parthenocarpic fruit) to 5 (parthenocarpic fruit). The Whitaker line produced parthenocarpic fruit and had a mean score of 4.2, whereas Caserta did not set parthenocarpic fruit and had a score of 1.55. The heritability estimates indicated that genetic gains from selection were feasible. The additive-dominant model showed a good fit, with epistasis being negligible or nonexistent. The hypothesis of monogenic inheritance with incomplete dominance was not rejected within the degree of dominance range from 0.2 to 0.5. These results indicate that parthenocarpy is controlled by a single locus, with incomplete dominance in the direction of parthenocarpic expression.