Evidence and Significance of Self-pollination of Avocados in Florida

Abstract

Pollination was investigated in five avocado (Persea americana Mill.) cultivars during two seasons. In the first year, `Simmonds' and `Hardee' branches with inflorescences were covered with cheesecloth bags to prevent pollination by large flying insects during either or both the first (Stage I) and second (Stage II) floral openings. Adjacent, tagged branches were left open as controls. The proportion of pollinated Stage I flowers ranged from <1% in `Simmonds' to 9% in `Hardee.' Pollination rates in Stage II ranged from 15% in `Simmonds' to nearly 69% in `Hardee'. Pollination during Stage II was proportional to the number of white stigmas available during that stage. Stage II pollination rates for bagged flowers and open flowers were similar, even though large flying insects were barred from bagged flowers. In the second year, similar experiments on cultivars Simmonds, Tonnage, Tower 2, and Choquette provided results consistent with those obtained the previous year. Virtually no pollination occurred in bagged Stage I flowers in all cultivars tested, and ≈1% of the open Stage I flowers were pollinated. Pollination of bagged and open Stage II flowers was generally the same within cultivars. The percent pollination of Stage II flowers ranged from a mean of 4.3% to 35%, depending on cultivar. The results show that self-pollination during the Stage II floral opening is the primary means of pollination of commercial cultivars grown in Florida. Moreover, the presence of developing fruits on branches bagged during the flowering season demonstrated that fruit set can occur without pollination by large flying insects.