this paper continues the statistical analysis of a coffee varietal trial at campinas (1, 2, 3), utilising the data of a further period of 4 years. variety d (yellow bourbon) has now drawn significantly ahead of c (bourbon) as is shown by fig. 1 compared with fig. 2b of reference (3). this possibility was foreseen at the time of the earlier analysis (3), from a consideration of the annual rates of increase of yield. this is of interest to the general problem of selection of perennial plants, because it shows that not only average yield but also rate of increase of yield is a useful criterion for selection.
