Factors Influencing Fruit Setting in the Pecan

Abstract

1. The pistillate flower of the pecan consists of an orthotropous ovule, surrounded by a single integument. The portion which becomes the shell consists of two carpels, which are transverse on the axis of the inflorescence. The 4-valved husk is developed from the lower portions of the calyx lobes. The flowers are sessile on the peduncle, and are borne in clusters usually of two to six. 2. The pollen tube grows down through the style and ovary wall or integument to the base of the ovule, and returns through the chalaza and nucellus to the embryo sac, fertilization occurring about 4 weeks after pollination. 3. There is a definite drop of young nuts about 4 weeks after the time of pollination, and this drop accounts for over 75 per cent of the seasonal drop. It appears to be due to lack of pollination. 4. The varieties tested show no evidence of self-incompatibility or inter-incompatibility. Good sets of fruit were obtained from any variety of pollen available when the flowers were receptive. 5. The period o...