Physiological characterization of sweet sorghum at different irrigation levels

• Autor(a) principal: Moreira, Luciano Rezende
• Data de Publicação: 2013
• Outros Autores: Ervilha, Jardélcio Damião Carvalho, Coutinho, Paulo Henrique, Vidigal, Juliana Gonçalves, Ogliari, Juares, Miranda, Glauco Vieira, Pereira, Lucas Felisberto
• Tipo de documento: Artigo
• Idioma: por
• Título da fonte: Vértices (Campos dos Goitacazes. Online)
• Texto Completo: https://editoraessentia.iff.edu.br/index.php/vertices/article/view/1809-2667.20130017
• topic: Water deficit; Chlorophyll fluorescence; Sorghum bicolor L.; Gas exchange; Déficit hídrico; Fluorescência de clorofila; Sorghum bicolor L.; Trocas gasosas

Sorghum [Sorghum bicolor (L.)Moench] is an African species belonging to the same family of maize. Saccharine-type sorghum is used as raw material for bioenergy (ethanol), and has high water-use efficiency. This study aimed to characterize sweet sorghum cultivars regarding physiological characteristics at different levels of irrigation. Four cultivars tolerant to drought were evaluated: Rio, Ramada, BRS 501, and BRS 506. Treatments consisted of three water availabilities: 80%, 60%, and 40% of field capacity. The study evaluated the stomatal conductance (gs), the net photosynthetic rate (A), leaf transpiration (T), and intrinsic water-use efficiency (EIUA, A/gs). It also determined the optimal quantum efficiency (Fv/Fm) of photosystem II (PSII), the quantum yield of photochemical processes in the basal PSII (Fo/Fm), and in PSII photochemical efficiency (Fv/Fo). The availability of water caused no change (P > 0,05) in transpiration in the Ramada and BRS 501 cultivars, but affected (P < 0,05) the Rio and BRS 506 cultivars, which responded positively to increased irrigation. A similar result occurred with photosynthesis, in which case the different levels of water availability had a positive influence only in the BRS 506 and Rio cultivars. The increase in irrigation resulted in an increase (P < 0,05) in stomatal conductance of the evaluated cultivars. The results of chlorophyll fluorescence showed the superiority of BRS 506, Rio, and Ramada with higher values (P < 0,05) of Fv/Fm and Fv/Fo. The different levels of water availability and cultivars did not promote (P > 0,05) change in EIUA. This methodology, common in other crops, can be used for saccharine-type sorghum in order to establish water availability in new experiments aiming at discriminating drought-tolerant cultivars.