In a split plot design, the fertilization response of four bread wheat varieties (Triticum aestivum L.) was studied. Three trials were carried out at the Quilamapu Research Station (INIA-Chillán), from 1983to 1985. Treatments (whole plots) were: Ti = check, no N, no P applied; T2 = 50 kg N/ha + 50 kg P2O5/ha; T3 = 100 kg N/ha + 100 kg P2O5/ha; T4 = 150 kg N/ha ÷ 150 kg P2O5/ha; T5 = 200 kg N/ha + 200 kg P2O5/ha. Subtreatments (subplots) were the semidwarf varieties Onda and Andifén and the talI varieties Vilufén and T-1500. The main conclusions were: - Semidwarf cv. produced higher grain yields than tali cv., mainly when N and P rates were equal or higherthan 100 kg/ha. - Harvest indexes in semidwarf (0.41) were 22.7% higherthan in talI wheats (0.34). - TalI varieties were less efficient than semidwarf in the use of N and P; grain production per kilogram of N and P2O5 applied were 14.6 and 26.2 kg, respectively. |