In an experiment carried out in a greenhouse of the Experiment Station of the Instituto Agronômico, Campinas, State of São Paulo, Brazil, in 1986/1987, eleven guineagrass genotipes were grown in nutrient solutions with four P levels. The objective was to evaluate them as to P uptake and use efficiency by determining dry matter yields and P accumulation and distribution in plant parts. Top dry matter yields increased more drastically than those of roots, in function of increasing P levels in nutrient solutions. The hybrids H55-B and H71-B showed higher top/root dry matter ratios for the levels of 2 and 4 mg P/liter, possibly correlated with higher top/root P content ratios. Phosphorus distribution or transport to the tops was the main characteristic for genotype differentiation. The levels of 2 and 4 mg P/liter, in 1.7 liter pots, were considered adequate for the selection of guineagrass in nutrient solution.
Panicum maximum Jacq.; phosphorus efficiency; uptake; use; distribution