EFFECT OF PHOSPHORUS NUTRITION ON GROWTH OF POTATO GENOTYPES WITH CONTRASTING PHOSPHORUS EFFICIENCY

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.