Field evaluation of tissue culture derived sorghum for increased tolerance to acid soils and drought stress

Plant tissue culture is being recognized as an important tool for generating useful variants for crop improvement. The objective of this research was to determine if improved tolerance to acid soil and drought stress can be generated in sorghum [Sorghum bicolor (L.) Moench] through tissue culture. Two environments were used to screen for enhanced field tolerance: (1) a low pH field in Griffin, Georgia for testing acid soil stress tolerance, and (2) an arid environment in Yuma, Arizona for testing drought stress tolerance. A population of 212 R 1 sorghum lines from tissue cultures of Hegari and Tx430 were increased in 1986. Screening was then conducted in both environments during 1987. Selected entries which showed improved tolerance were advanced and re-tested during 1988. From this original population, four lines were identified as having improved acid soil tolerance and five lines were identified as having improved drought tolerance as compared to the non-regenerated checks. Three of these lines performed better than the non-regenerated checks under both acid soil and drought stress conditions. These results indicate that somaclonal variants for increased tolerance to environmental stresses can be generated in tissue culture and be selected under proper field conditions.Key words: Sorghum bicolor, somaclonal variation, drought tolerance, acid soil tolerance, tissue culture