Variability in the resistance of sodium chloride salinity within rice (Oryza sativa l.) varieties

Varieties of rice differ in their resistance to sodium chloride salinity. Within varieties, which are not homozygous lines, there is very high variability in sodium uptake and in survival under saline conditions by the individual plants. This is in contrast with the relative uniformity in (for example) potassium uptake, dry wt and transpiration rate. There is a negative correlation between sodium (and chloride) accumulation by individual plants and their survival in saline conditions, demonstrating that variability amongst individuals fits the same pattern as has become generalized for varietal differences in glycophyte species. Possible reasons for this variability in sodium and chloride uptake within varieties, and its relevance to selecting salt-resistant varieties of rice, are discussed.