Genetic variability of salinity tolerance in spring wheat (Triticum aestivum L.)

Salinity is one of the most damaging agro-environmental problems limiting plant growth and development in most parts of the world. The problem of salinity existed long before human beings and the start of agricultural practice and today it has become a very serious problem for crop production, particularly in arid and semi-arid regions, which constitute about one third of the world's land surface. The magnitude of genetic variation for salinity tolerance in spring wheat and broad-sense heritabilities has been estimated at different salinity levels. The 68 genotypes responded with different behaviors to increasing salinity levels in the growing medium. Responses of different genotypes to increased salinity levels in reduced growth were found, with those originating from Australia exhibiting a significant increase in salinity tolerance compared with others, originating from Pakistan. Plant vigor and salinity tolerance were found to have no significant correlation as measured by relative growth rates in saline environments. The relative growth rate of various accessions grouped on the basis of different geographic origin and different genes of various stresses also were not different significantly from each other, which suggests that different genes may be controlling the characteristic, from a single major dominant or from recessive genes. Estimated broad-sense heritability indicated that phenotypic variance exceeded that of genotypic by nearly two orders of magnitude. This study was to determine genetic and phenotypic relationships between plant performance in the presence of NaCl at three developmental stages in wheat. These results suggest that improvement in salinity tolerance in spring wheat is possible through selection and breeding.