Grain Sorghum Grown Under Drought Stress at Pre- and Post-flowering in Semiarid Environment

摘要

In the current scenario of climate change, sorghum crop has high growth potential, requiring adaptation and selection studies for the various Brazilian production environments. Sorghum is among the most drought-tolerant cereals; however, extended summer can reduce the size and number of grains in the plant, reflecting into poorer yields. Sorghum breeding programs aim to develop hybrids more tolerant to water deficit, to ensure profitable yield even in the face of drought stress. The objective of the present study was to evaluate the effects of water restriction on grain sorghum hybrids in the pre- and post-flowering phases in the Brazilian semiarid. Twenty-five hybrids were evaluated under controlled irrigation conditions in Nova Porteirinha-MG and Teresina-PI. In the Nova Porteirinha, the hybrids were cultivated under conditions of non-drought stress and with drought stress in pre- and post-flowering stage. On the other hand, in Teresina, the experiment took place with non-drought stress and drought stress at post-flowering stage. The experimental design was in randomized complete blocks, in factorial scheme, with three replications. Drought stress reduced grain yield by more than 40%, showing that even being resistant, sorghum is affected by drought. Hybrids 1168093, 1167092, 1236020 and 1423007 showed high yields in the various environments, outyielding the commercial controls, what allows the recommendation of these cultivars for the semiarid areas or late off-season in the Cerrado region.