The yield response model is very important in irrigation planning and
management of irrigation projects. A computerized model for simulating irrigation
water requirement for wheat crop at Mosul area has been proposed for (20)years of
daily climatological data. The model predict daily actual and potential
evapotranspiration, then the relation between relative yield and relative
evapotranspiration is put into (20)equations and solved mathematically to find the
coefficients for each stage of growing growth period of wheat crop at Mosul
area.The yield response factors is found for two cases, the first is for rainfed
agriculture practice for wheat for (20)years where an available data for production is
available ,and the second is for irrigated practice where four years production data
were available[1] .Then the results are compared with the results obtained from
(Doorenbos & Al kassam 1979) equation for yield. [2] and show a small variation
while the last equation is justified by International Agriculture and Food
Keywords: crop water production function ,yield response factor, yield Jensen
model, irrigation managemen