Can Technology Deliver on the Yield Challenge to 2050?
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This paper focuses on the yield prospects of wheat, rice and maize since these cereals dominate human diet, and since continued yield growth is considered the major route to meeting future global demand for food, feed and fuel. We define for a region farm yield (FY), attainable yield (AY, as reached with the best technology and prudent economics), and potential yield (PY, yield with the best varieties and agronomy and no manageable biotic or abiotic stresses). FY progress is a function o f progress in PY and in closing the gap between PY and FY (we express this gap as a percent of FY). Globally wheat and rice annual yield increases (as a percent of current yield) are falling and are now just below 1 percent, while that for maize is 1.6 percent. For rice and wheat, the growth of yields in absolute terms (kg/ha/year) are also falling in developing countries. Global demand modelling to 2050 predicts large real price sensitivity to yield growth rates, with significant pric e increases if current rates cannot be increased. FY, PY and yield gaps are examined in more than 20 important “breadbasketâ€Â regions around the world. For wheat annual PY progress currently averages about 0.5 percent, and the yield gap 40 percent (range 25 to 50 percent), while for rice PY growth is also about 0.5 percent while the yield gap averages 75 percent (range 15 to 110 percent). Maize is distinctive with a current average PY growth of around 1 percent and a yield gap which r anges from around 30 percent (Iowa, some uncertainty with PY) to over 200 percent (sub-Saharan Africa). A yield gap of 25 percent or less probably implies that FY is approaching attainable yields, AY. Yield gaps tend to be larger in developing countries, and seem to be closing only slowly except in the case of maize in Iowa and major cereals in Egypt.