This study was based on the hypothesis of existence of genetic variability among genotypes of wheat (Triticum aestivum L.) in relation to the nitrogen utilization and response to application of this nutrient. The experiments were carried out at the Campinas and Tatuí Experiment Stations, Instituto Agronômico, State of Sao Paulo, Brazil, under sprinkler irrigation conditions, in succession to fallow (Campinas) and rice or lablab crops (Tatuí), during 1987-1991 years. It was used a randomized complete block design in a split plot arrangement with four replications. The main plots were the levels of nitrogen (0, 60 and 120 kg/ha) and the split-plots were the wheat genotypes: BH-1146, IAC-5, IAC-24, IAC-25, IAC-60, IAC-161, IAC-162 and Anahuac. The results showed that in relation to the grain yield, the most productive genotypes were IAC-60, IAC-161 and IAC-162 which responded up to 120 kg/ha of applied nitrogen and the remaining responded only to 60 kg/ha of N, in Campinas during 1991. At the Tatuí Experiment Station, in 1987, the most productive genotypes were IAC-60 and IAC-24 and all genotypes responded up to 120 kg/ha of applied nitrogen; but they did not respond to the high levels of applied nitrogen, during the years 1988 to 1990, in succession to lablab crops.
nitrogen; wheat; Triticum aestivum L.; response and efficiency