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. 2013 Dec 17;4:2918. doi: 10.1038/ncomms3918

Figure 8. Trendline residuals for maize yield plotted against year for selected regions.

Figure 8

Selected regions are indicated in the right axis labels. Only one residual plot is shown for either the piecewise (PW+, PW−) or linear plateau with upper/lower plateau (LUP/LLP) because these models are mutually exclusive. The y axis scale is the same across all panels and is shown only in the upper and bottom panels. Asterisks indicate significance at F-test *P<0.01 or **P<0.001 of the fitted regression line to the residuals over time (n=46 years of yield data, except for USA (n=47)). L, linear; QP, quadratic plateau; PW, piecewise with (+) increasing or (−) decreasing rate after breakpoint year; LUP/LLP, linear with upper/lower plateau; EXP, compound exponential; R, rainfed; I, irrigated.