Full Length Research Paper

Sorghum stem yield and soluble carbohydrates under different salinity levels

A. Almodares¹*, M. R. Hadi² and H. Ahmadpour¹

¹Department of Biology, Faculty of Science, University of Isfahan-Iran.

²Research Department of Potato Biotechnology, University of Isfahan-Iran.

*Corresponding author. E-mail: aalmodares@yahoo.com.

Accepted 25 August, 2008

The aim of this study was to select the most suitable cultivar for salty land in this geographical area. Two sweet sorghum cultivars (Keller and Sofra) and one grain sorghum cultivar (Kimia) were grown in greenhouse benches under four salinity levels of 2, 4, 8 and 12 dSm^-1 to evaluate the effects of salinity on stem yield and  soluble carbohydrate (sucrose, glucose and fructose). The results showed that in all cultivars as salinity increased, the amount of stem yield and soluble carbohydrate decreased. In all salt concentrations, Keller and Kimia had the highest and the lowest stem yield and sucrose, respectively. At the highest salt concentration (12 dSm^-1), Keller had the lowest stem yield reduction (less than 1%) and  the highest sucrose content while Kimia  had the highest stem yield reduction (more than 18%) and  the lowest sucrose content. Therefore, Keller and Kimia can be considered as salt tolerance and salt sensitive cultivars, respectively. As salinity increased, the amount of glucose and fructose in Keller decreased while they increased in Sofra. Increasing glucose and fructose in Sofra is not an indication of its salt tolerance. At the physiological maturity stage, the plant has the highest stem yield and sucrose content while it has the lowest glucose and fructose content than flowering stage. Base on the results, Keller is recommended to be planted under soil salinity conditions and harvested at physiological maturity stage.

Key words: Sweet sorghum, grain sorghum, salinity, stem yield, sucrose, glucose, fructose.