Determining the salt tolerance of triticale disomic addition (Thinopyrum additions) lines

Biotic and abiotic stresses constitute an increasing problem, and in and and semi-arid regions salinity and drought stress are especially severe. Saline soils can be treated, but it is expensive and temporary. An obvious solution is to modify the plant to cope with salinity. Unfortunately the genetic and physiological bases of salt tolerance are not well understood as the trait is under polygenic control in most crop species including cereals. Accessible sources of salt tolerance genes are hard to come by. Thinopyrum distichum (2n = 28) is an indigenous grass native to the coast of the Western Cape province of South Africa. A project was initiated to transfer the salt tolerance of this grass to commercially cultivated triticale and wheat. Disomic additions were made of specific Th. distichum chromosomes believed to contribute to salt tolerance. This study developed and optimized screening techniques to differentiate among these addition lines with the aim of determining their potential contribution to salinity tolerance. Methods included growth and/or yield assessment, detection of damage or tolerance symptoms, and quantification of physiological changes. The results indicated that methods to detect growth or yield reduction gave the best overall correlation with salinity tolerance