Crescimento e produção de gergelim (Sesamum indicum L.) em função de lâminas de água

Abstract

Sesame is an important oilseed crop and can be grown in tropical and subtropical regions around the world, such as the Northeast of Brazil. Its seeds have oil of high nutritional and protein content, used in the food industry and pharmaceutical, cosmetics and biofuel. However, in the Northeast there is irregularity rainfall and high evapotranspiration rates witch usually prejudice agricultural production and research development in order to select genotypes with characteristics of tolerance to these conditions. In this context, this study was carried out in order to evaluate growth, physiology and production of sesame genotypes under different rates of water replacement. The experiment was accomplished from September to December 2012 at the Experimental Station of Embrapa Algodão, Barbalha, CE, under field conditions. The randomized block design was adopted with treatments in a factorial (4 × 6), corresponding to four irrigation levels (40, 70, 100 and 130% of ETo) and six genotypes (G1=T3-EGSGO3; G2=T7-EGSGO7; G3=T5-EGSGO5; G4 =T2-EGSGO2; G5=T6-EGSGO6 and G6=T4-EGSG04) with three replications. During experiment were collected growth variables (leaf area, plant height and stem diameter), physiological and biochemical (relative water content, disruption of the cell membrane, content of photosynthetic pigments, carbohydrates and protein in leaves and root and peroxidase and catalase activity) and production (dry matter, oil content in seeds and productivity). Harvesting of Sesame was performed manually at 95 days after sowing. Higher growth and production occur using irrigation levels between 75 and 90% ETo. The content of pigments, chlorophyll b, and total carotenoids were enhanced with application of 80% ETo. The enzymatic activity of sesame cultivars was reduced in plants under drought stress by deficiency or by water excess. Maximum production potential of sesame is found with application of water levels in 75-90% of ETo.