Resumen
Due to the importance of the soybean complex on the world economy, there is concern about the significant losses of the full production potential due to abiotic stresses, so that drought is the main challenge for production. Genetic engineering allows insertion of specific genes in order to develop more drought tolerant cultivars. This study aimed at evaluating field agronomic responses of conventional soybean cultivars (BR 16 and Embrapa 48) under water deficit conditions, in comparison to the soybean lines 1Ab58 and 1Bb2193, genetically modified (GM) for drought tolerance with rd29A:AtDREB1A and rd29A:AtDREB2A constructions. The conventional cultivar Embrapa 48 was the genotype most benefited by the abundance of water (IRR), but with no differences in yield compared to other plant materials under such conditions. Although the crossing 09D-0077 (BR 16 x 1Ab58) presented the highest leaf area index (LAI) values under IRR, such a genotype had a similar performance to GM lines (1Ab58 and 1Bb2193), including in yield, thus indicating that backcrossing and transforming elite lines showed similar responses to water deficit. Further studies are needed in order to confirm the potential of GM lines and the crossing 09D-0077 to cope with drought under more severe water deficit conditions.