Herança da tolerância ao estresse hídrico em tomateiro

Abstract

Climate change is expected to affect the demand for irrigation water by possible changes on rainfall patterns, temperature extremes and crop transpiration. Tomato lines were obtained with high levels of tolerance to fruit blossom-end rot induced by water stress. Nevertheless, a study of the inheritance is needed in order to develop suitable strategies for the development of tolerant genotypes. Thus, the first part of this work was to study the inheritance of incidence to blossom-end rot in tomato fruit induced by water stress, showing that a major gene with dominance effect, whose gene action is influenced by polygenes (modifiers), also predominantly dominant gene effects, controls the incidence to blossom - end rot. In the second part of the work was to study the inheritance of tolerancewaterstress in tomato, related with the abaxial and adaxial stomatal density, and to estimate the correlation between tolerance to blossom-end rot induced by water stress and stomatal densities. The inheritance of adaxial stomatal density is controlled by a single gene locus with predominantly additive effects, with no evidence of poligenes modifiers. The mean stomata valuesin the adaxial surface were highly correlated to the mean of the blossom-end rot percentages of the populations studied. The high correlations recorded of traits in study indicate that selection for lower stomatal density in adaxial surface of the leaflets may be effective in order to provide greater tolerance to tomato blossom-end rot induced by water stress.