FLOWERING BEHAVIOR AND 2N POLLEN PRODUCTION IN DIHAPLOID SOLANUM-TUBEROSUM X SOLANUM-CHACOENSE HYBRIDS

The flowering characteristics of 81 dihaploid Solanum tuberosum (2n=2x =24) x Solanum chacoense (2n=2x=24) hybrid clones were studied. Two sc reenhouse experiments were carried out in the Biology Department at '' Escola Superior de Agricultura de Lavras'' between October and Decembe r 1991 (Spring) and March and May 1992 (Fall). The experimental design used was randomized complete blocks with three replications. Each exp erimental unit (plot) was formed by a single plant. The results showed wide variation among the clones for all the characteristics assessed. Clone flowering was abundant in both periods but more pronounced in t he Spring. Clones were found with high 2n pollen frequencies making th em promising for 4x - 2x crossings. The frequency and viability of 2n pollen were higher under mild temperatures (Fall). The amount of polle n produced on the anthers was normal and did not show any significant difference between the flowering periods.