A POTENTIAL SOURCE OF VARIATION FOR SALT TOLERANCE IN SPRING WHEAT

Salt tolerance of spring wheat cultivars, the salt sensitive Punjab 85, the salt tolerant LU26S, and an F2 bulk population was assessed after two weeks growth at varying concentrations of NaCl + CaCl2 (1:1 by wt.) in nutrient solution. Cv LU26S had significantly longer shoots and roots, and greater fresh and dry plant matter than Punjab 85 and the F2 population. Root lengths and fresh weight of the F2 material and Punjab 85 did not differ. The F2 population had longer shoots at 8, 16, and 24 dS m-1 and greater plant dry matter at 8 dS m-1 than Punjab 85. The F2 population was considerably more variable in all salinity treatments than LU26S and Punjab 85 for all the growth characters measured. From 10,000 seeds of the F2 bulk population screened in a programme with repeated salinity treatment at two growth stages in sand culture, only 6 plants produced seed, from which adult plants were raised to provide selected salt tolerant population seed. Grain yield of the selected population was compared with that of LU26S and Punjab 85 in a sand culture experiment salinized with NaCl + CaCl2 (1:1 by wt.) at EC values of 2.8 (control), 10, and 20 dS m-1. The selected population had significantly greater seed yield than Punjab 85, but did not differ from LU26S in any of the yield parameters measured. It is suggested that improvement in salt tolerance in wheat may readily be achieved through conventional selection and breeding techniques, using segregating F2 or F3 generations from normal breeding programmes.