Seleção fenotípica de híbridos de sorgo granífero submetidos à restrição hídrica em pré e pós-florescimento

Abstract

This study aimed to evaluate the effects of water restriction in pre- and post-flowering grain sorghum hybrids cultivated in semi-arid regions. Two field experiments were conducted in Nova Porteirinha-MG and Teresina-PI. In both places, 25 hybrids of grains sorghum were evaluated, in randomized blocks, with three replicates. In Nova Porteirinha, the hybrids were cultivated in environments without water restriction, with water restriction in pre-flowering and with water restriction in post-flowering. In Teresina, the hybrids were evaluated in environments without water restriction and with water restriction in post-flowering. The number of days for flowering, plant height, 1,000 grain mass and grain yield were evaluated at two evaluation places. The machine efficiency and root angle were evaluated only in Nova Porteirinha-MG. Water stress influenced the flowering of hybrids just a little, but reduced plant height, 1,000 grain mass, and grain yield. The water restriction reduced productivity by more than 40%, but it was possible to find hybrids with optimal performance under these conditions. The most stable and promising hybrids were 1168093, 1167092 and 1236020. Water stress in pre-flowering impaired plant height, accelerated flowering, and reduced hybrids productivity by 45%. The 1,000 Brains mass was not influenced by the stress in pre-flowering, indicating that the reduction of the grain yield was due to the reduction in the number of grains. Post-flowering stress influenced mainly the machine efficiency and the 1,000 Brains mass, reflecting a 48% reduction in grain yield.