GENOTYPIC DIFFERENCES TO SOIL-SALINITY IN CLUSTERBEAN

This study relates the changes in performance (dry matter, seed yield, and leaf area), mineral composition (N, P, K, Na, and Cl), concentrat ions of leaf metabolites (chlorophyll, starch, reducing sugars, solubl e protein, free proline, and free amino acids), and activities of nitr ate reductase and glutamine synthetase at soil salinity of 10 dS m(-1) in 10 genotypes of clusterbean (Cyamopsis tetragonoloba Taub.). Based on the extent of reduction in seed yield, genotypes were initially ca tegorized as tolerant (Malosen and HFG-182), moderately tolerant (AG-1 11, Kutch-8, KVS-2, DP Safed, and B-22-11-55), and sensitive (Durgajai , FS-277, and B-31-1-55) to increased salinity. The responses between the tolerant and sensitive genotypes to salinity were different in all the parameters considered here. The responses of the moderately toler ant genotypes to salinity were variable and inconsistent, The sensitiv e genotypes had higher concentrations of Na and Cl in the shoot tissue and also a lower K:Na ratio under stress as compared to tolerant geno types. Some sensitive (FS-277) and moderately tolerant genotypes (DP S afed, KVS-2, and Kutch-8) provided Yields comparable to tolerant ones under salt stress because of their high yield potential. Reliable eval uation of tolerance to salinity seems to warrant consideration of dive rse physiological parameters in a fairly large number of genotypes.