Comparative ammonia and nitrate accumulation in drought tolerant and susceptible wheat genotypes under soil water deficit conditions

Experiments were conducted in lysimeters during two consecutive years. During the first year eight wheat genotypes were compared for growth and yield under water stress conditions and in the following year the tolerant and susceptible genotypes were compared for the accumulation of nitrate and ammonium under the same environmental conditions. Each experiment cmprised four water deficit treatments with four replications. The results showed that growth and yield were reduced at all water stress treatments in all the wheat genotypes, however, more pronounced in DS-17 and Pavon. Ammonium and nitrate accumulation increased in all the wheat genotypes under water stress conditions, which was further enhanced with the intensity of stress. The maximum accumulation of ammonium and nitrate was observed under terminal drought followed by post-anthesis drought and pre-anthesis drought. The highest accumulation was in the drought susceptible genotypes. Tolerant genotypes had higher growth and yield, but had lower accumulation of nitrate and ammonium. Negative correlations were observed among growth, yield and accumulation of ammonia and nitrate. From the results, it can be concluded that on the basis of ammonia and nitrate accumulation drought tolerant and susceptible genotypes can be isolated.