Resumo

CASTRO-NAVA, S; ORTIZ-CERECERES, J; MENDOZA-CASTILLO, M del C  e  HUERTA, AJ. Biomass production and grain yield of three sorghum lines difering in drought resistance. Phyton (B. Aires) [online]. 2012, vol.81, n.2, pp.149-156. ISSN 1851-5657.

The aim of this study was to determine the eficiency of drought classification criteria that we previously reported for our grain sorghum genotypes. Two tolerant genotypes of grain sorghum [Sorghum bicolor (L.) Moench] (UAT-124 and UAT-152) and one susceptible (UAT-30) were subjected to drought under greenhouse conditions at either panicle initiation, flag leaf, or flowering. Results showed that the effects of drought depended on when drought stress occurred during development. Biomass of the three sorghum genotypes was significantly reduced at the flag leaf stage (48%) by drought stress, but the greatest reduction occurred in the susceptible genotype UAT-30 (71%). Results showed that biomass accumulation for UAT-124 and UAT-30 was strongly in accordance with our previous drought classification, but this was not true for UAT-152. Drought stress reduced grain yield significantly in all genotypes, when it was applied at fag leaf stage (24%) and at flowering (28%), but not at panicle initiation. Resistant and susceptible genotypes had the same response in terms of grain yield when stress was applied at any of the three phenological stages. The results indicate that genotype responses to drought treatment were inconsistent with their initial classification. The identification of tolerant and susceptible sorghum genotypes could be better accomplished by applying drought stress at the more susceptible stage of development, flag leaf, and selection must be based on biomass, grain yield and leaf area.

Palavras-chave : Sorghum bicolor L. Moench; Water stress; Drought; Phenology; Biomass accumulation; Grain yield.

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