Productivity and drought tolerance of cassava cultivars in the Coastal Tablelands of Northeastern Brazil

Ten cassava cultivars were grown in the field and evaluated to identify the most adapted to the Coastal Tablelands of northeast Brazil. The cultivars showed differences in proline and chlorophyll contents, plant height, number of leaves and branches, canopy area and root production, however they did not differ on photosynthetic rates. Cultivars 'Tiangua' and '9783-13' presented lower root yield, whereas 'BRS Tapioqueira' and 'Irara' had the highest root yield. Few leaves coupled with the highest water use efficiency for CO 2 assimilation was found in 'BRS Kiriris' in contrast to 'BRS Jarina' and '9783-13'. 'BRS Caipira' had high proline content in both Umbauba and Frei Paulo areas, traits usually associated to drought tolerance, that contribute to the adaptation. It is also important to consider that cultivar 'BRS Caipira' was the first to present increase in chlorophyll content after extended period of drought, that indicates a faster recovery after dry season. Furthermore, the results indicated that the most adapted cultivars for cultivation in this area are 'Irara', 'BRS Tapioqueira', 'BRS Kiriris' and 'BRS Caipira'.