PHOSPHORUS ACCUMULATION AND TRANSLOCATION IN WHEAT AS AFFECTED BY CULTIVAR AND NITROGEN-FERTILIZATION

To improve nutrient management strategies in wheat more information is needed about the interaction effects among nutrients in their uptake and redistribution in the plants, in relation to different genotypes. Therefore, two bread (T, aestivum L.) and two durum (T, durum Desf.) w inter wheat cultivars were grown in the field for 2 years (1986, 1987) in a silty-clay soil under different nitrogen (N) levels, in Northern Greece. Nitrogen at a rare of 150 kg ha(-1) was applied before planti ng or 100 kg ha(-1) before planting and then 50 kg ha(-1) at early boo t stage. Cultivar differences in phosphorus (p) concentration were obs erved only in vegetative parts but. not in the grain. Maximum p accumu lation was observed either at anthesis or at maturity. During grain fi lling dry matter and p accumulation in the grain followed almost the s ame pattern. Phosphorus translocation efficiency of the cultivars at t he 2 rears ranged from 70.7 to 84.3% and the amount of p in the grain derived from translocation 52 to 100%. Phosphorus translocation effici ency was weakly correlated with p content in grain only in 1986, while phosphorus harvest index (PHI) was positively correlated with harvest index (HI) both years (r = 0.82* in 1986 and 0.75** in 1987). Nitrog en application mainly affected p accumulation of the cultivars via its effect on biomass production. The split N application promoted slight ly the p uptake in 1987 and this resulted in the reduction of both the contribution of the translocated p to the grain and the efficiency of p utilization for total biomass. Results indicated that p accumulatio n and translocation and the efficiency of p utilization in wheat were mainly determined by the genotype in relation to environmental conditi on of growth.