Tolerance of brachiaria hybrids to water stress

Abstract

Knowledge about tolerance to water stress is important to choose the grass appropriately according to the different edaphoclimatic conditions. Therefore, the objective of this research was to verify the tolerance of hybrids of Brachiaria spp. stress due to water deficit and flooding. Experiment was done in a greenhouse, in completely randomized experimental design, with twelve treatments, in a 4x3 factorial scheme, and three replications. Treatments adopted were four grasses, three hybrids of Brachiaria spp. (Camello, Cayana, Cayman) and B. humidicola cv. Llanero, which were submitted to three water conditions (water deficit, without water stress and flooding). Grasses were subjected to water stress for 47 days and during this period two evaluations were performed. For all grasses, the water deficit led to a reduction in the tillers number and the water deficit and flooding promoted a reduction in the leaves number, with a greater impact on the water deficit. Flooding did not compromise the forage mass of Brachiaria humidicola cv. Llanero, which demonstrated the tolerance of this grass to this water stress. For all hybrids, there was a reduction in forage mass production when subjected to water stress (deficit and flooding). Water deficit promoted lower forage mass than flooding for all hybrids studied, with the exception of Cayana, which was equally affected by water deficit and flooding. Water deficit reduced the root mass of all grasses, while flooding reduced the root mass of Camello and Cayana grasses. It was observed that Brachiaria humidicola cv. Llanero and Cayman grass have greater tolerance to flooding, since in this condition there was no reduction in root mass. Therefore, none of the hybrids is tolerant to water deficit and Cayman is the hybrid with the highest tolerance to flooding