Potato (Solanum tuberosum L.) has high phosphorus requirement for optimum growth and yield. Thus, under
P deficiency, growth and yield are considerably reduced. An experiment was conducted in a controlled growth
chamber on the effect of P supply on morphological and physiological plant parameters of three potato genotypes
having contrasting P efficiency. The genotypes were CGN 17903, CIP 384321.3 and CGN 18233. They
were grown under two P levels [100 mg P kg-1 soil (low P) and 700 mg P kg-1 of soil (high P)]. Treatments were
arranged in a completely randomised block designs with six replications. Low P supply reduced shoot dry matter
yield, relative growth rate, leaf number, whole plant relative leaf expansion rate, total leaf area per plant, plant
height and net assimilation rate of P-inefficient genotype, more than that of the P-efficient genotypes. However,
low P supply did not affect net photosynthetic rate per unit leaf area, leaf dark respiration rate, chlorophyll
fluorescence rate and electron transport rate of both P-efficient and inefficient genotypes. P-efficient genotype
CGN 17903 allocated more dry matter yield to the leaf which might have enabled higher light harvesting, hence
contributing to high biomass accumulation of this genotype.