Phosphorus nutrition of cotton cultivars under deficient and adequate levels in solution culture

In low-input agricultural systems that characterize most of the developing world, nutrient-efficient crop cultivars may play significant role in improving crop productivity, Phosphorus (P) deficiency is a common phenomenon in cotton growing areas of Pakistan, however the farmers are reluctant to apply it due to its price and fear of lack of response. A solution culture experiment was conducted to evaluate 10 commonly grown cotton cultivars for their relative efficiency to utilize deficiently and adequately supplied P, using Johnson's solution. Phosphorus deficiency markedly reduced shoot dry weight (SDW), root dry weight (RDW), whole plant dry weight controlled by plant P contents under P deficient conditions, suggesting an internal regulation in addition to the influence exerted by external P supply. The conclusions from experiment were that differences in growth existed among cotton cultivars exposed to same P concentration in the growth medium. Cultivars, which were efficient in both P-acquisition and P-utilization, were efficient accumulators of biomass under adequate as well as deficient level of P supply.