Further observations on the relationship between growth and yield in cocoa varieties

Yields of cocoa varieties are positively correlated with the rate of trunk diameter increase prior to commencement of bearing, the correlation persisting over the years and not deriving only from faster-growing varieties being first into bearing. However yields seem to be more closely correlated, over early and intermediate years, with the difference between the rate of trunk diameter increase while in bearing and that in the pre-bearing period. Over these years there is a negative relationship between yields and the current rates of trunk diameter increase. Once varieties are well into bearing, current trunk diameters have little influence on yield.The rate of trunk diameter increase slows down until, in later years of bearing, it is almost nil. Then yields may be very closely correlated with the rates of diameter increase before bearing, which in effect are the same as the reductions in increment rates.A difference between varieties of 1.2 cms. per annum in the pre-bearing rate of trunk diameter increase seems to be roughly equivalent to a difference in yielding capacity of 1,600 lbs. dry cocoa per acre per annum.