Author(s): SOUZA, A. A. de; CARVALHO, A. J. de; BASTOS, E. A.; CARDOSO, M. J.; JÚLIO, M. P. M.; BATISTA, P. S. C.; JÚLIO, B. H. M.; CAMPOLINA, C. V.; PORTUGAL, A. F.; MENEZES, C. B. de; OLIVEIRA, S. M. de

Summary: Sorghum is one of the most drought-tolerant cereals. However, strong water stress, especially during the reproductive phase, causes significant grain yield reduction. Drought events are common in second crops planted after soybean harvest in Brazil. The objective of the present study was to assess grain sorghum hybrids grown under pre- and post-flowering drought stress. Twenty-five hybrids were subjected to two water stress environments (pre- and post-flowering) and one environment with non-water stress. The experimental design was a split plot based on a randomized complete block with three replicates. Water stress pre-flowering reduced plant height, accelerated flowering, and increased panicle index compared with water stress post-flowering. Both pre- and postflowering stress reduced yield, by 45% and 48%, respectively. Grain mass was greatly affected by stress occurring post-flowering but not by that occurring pre-flowering. Therefore, the reduction in yield caused by pre-flowering stress is due more to the reduction of grain number in the panicle, whereas the reduction when stress occurs post-flowering is due more to reduction in grain size. The plant chlorophyll index decreased when stress occurred pre-flowering and reverted after irrigation had resumed, demonstrating recovery in the photosynthetic capacity of the sorghum plant. With post-flowering stress, the chlorophyll index decreased significantly 30 days after the stress, affecting grain filling, with consequent yield loss.

Publication year: 2021

Types of publication: Journal article

Unit: Embrapa Maize & Sorghum

Keywords: Abiotic stress, Chlorophyll index, Estresse abiótico, Estresse hídrico, Semiárido, Sorghum Bicolor, Sorgo Granífero, Water stress, Índice de clorofila