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 impro ving crop productivity, Phosphorus (P) deficiency is a common phenomenon in cotton growing areas of Pakistan, however the farmers are reluctant to app ly it due to its price and fear of lack of response. A solution culture exp eriment was conducted to evaluate 10 commonly grown cotton cultivars for th eir relative efficiency to utilize deficiently and adequately supplied P, u sing Johnson's solution. Phosphorus deficiency markedly reduced shoot dry w eight (SDW), root dry weight (RDW), whole plant dry weight controlled by pl ant P contents under P deficient conditions, suggesting an internal regulat ion in addition to the influence exerted by external P supply. The conclusi ons from experiment were that differences in growth existed among cotton cu ltivars exposed to same P concentration in the growth medium. Cultivars, wh ich were efficient in both P-acquisition and P-utilization, were efficient accumulators of biomass under adequate as well as deficient level of P supp ly.