Various authors give different figures for the yield increase obtained by reproductive pruning. Martinez (1936) states that increases of up to seven times the yieldon non-reproductively pruned plants have been obtained in Mexico. Castellanos etal. (1996) report yield increases from 140 to 340% when testing the three highestyielding Mexican cultivars, whereas Grum et al. (1996) recorded yield increases offrom 7 to 39% when testing 32 accessions in Tonga. This effect is most certainly environmental