The results of eight month tappings (half-spiral cut) of 100 seedlings of rubber trees, 30 years old, are presented. From May to July 1943 the trees were tapped every day; from August to December, every other day. The change of the tapping system, from daily to every other day, caused an increase in the individual yield, per tapping; this yield increase was more pronounced in the low production plants. The study of the plants as a group presented the following results, respectively for daily and every other day tapping systems: a) 10% of the population yielded 31 and 31 % of the total production; b) 25% of the population yielded 58 and 57% of the total production; c) 50% of the population yielded 83 and 80% of the total production; d) 75% of the population yielded 95 and 94% of the total production. The results show the possibility of using unselected seeds as commercial planting material, provided the seedlings are planted at very high density in the field, in order to permit the elimination of most of the plants (the lowest yielders).