GROWTH-RESPONSES OF 12 WHEAT CULTIVARS AND THEIR PHOSPHORUS UTILIZATION FROM ROCK PHOSPHATE

Growth responses of 12 wheat cultivars and their phosphorus utilizatio n were studied in a greenhouse. They were grown for 18 days in a solut ion containing rock phosphate as the phosphorus (p) source. Biomass of 26 day old plants of all the cultivars varied significantly whereas t heir shoot to root ratio stayed constant. The dry matter yield of all the 12 cultivars was significantly correlated with the p uptake (r = 0 .74). Whereas the higher p uptake by all the cultivars was significant ly (P < 0.01) related to the drop in the root medium pH, which was pre sumably owing to the H+ efflux from their roots. The wheat cultivar Bl ue Silver proved to be the most efficient p user and therefore seems t o have the highest potential of making best growth in soils with poor p availability among the 12 wheat cultivars under investigation.