FIGURE 1. Fruit yields of three apple production systems.
From the following article:
Sustainability of three apple production systems
John P. Reganold, Jerry D. Glover, Preston K. Andrews and Herbert R. Hinman
Nature 410, 926-930(19 April 2001)
doi:10.1038/35073574
Differences between values in a year followed by different letters are significant at the 0.05 level (least significant difference).