Effects of storage length and flowering stage of pollen influence its viability, fruit set and fruit quality in ‘Red’ and ‘Lessard Thai’ sugar apple (Annona squamosa) and ‘Gefner’ atemoya (A. cherimola × A. squamosa)

• Pollen from sugar apple and atemoya may be stored for up to 24 and 48 h, respectively.
• Annona species present distinct behavior for in vitro pollen germination.
• Sugar apple and atemoya are highly dependent on hand pollination.
• The success of hand pollination is directly correlated to the pollen viability.
• Fruit quality is significantly associated with the management of pollination.

The fruit set of commercial Annonaceae pollinated by natural pollinators is generally insufficient to produce commercially acceptable yields. In addition, several studies have reported that both the pollen source and age affect the potential percent fruit set of sugar apple and atemoya. Annona flowers are hermaphrodite; however, the female part mature before the male, which is known as dichogamy of the protogynous type. The objectives of the present study were to determine the effect of pollen storage duration on pollen viability; the percent fruit set by hand pollination of ‘Red’ sugar apple, ‘Lessard Thai’ green sugar apple and ‘Gefner’ atemoya; and resulting fruit characteristics as a result of pollen source in South Florida. Hand pollination and in vitro pollen germination tests were arranged in a 3 × 5 factorial design, with three cultivars, five treatments, and five replicates per treatment. The percentage of in vitro pollen germination was the highest for ‘Red’ sugar apple pollen (26.5%) collected from male stage flowers and for pollen collected from female stage flowers collected late afternoon and germinated 18 h later (23%). Percent pollen germination was higher for ‘Lessard Thai’ (∼33%) than for ‘Red’ sugar apple and pollen storage for up to 24 h was not significantly different than male stage pollen used immediately and pollen collected from female stage flowers and used 18 h later. ‘Gefner’ atemoya pollen did not germinate when pollen grains were collected from male stage flowers and when using female stage flowers collected late afternoon and stored for 72 h. Fruit set and fruit quality varied significantly as a result of pollen storage treatments. Hand pollination promoted high percentages of fruit set, greater than 80% when female stage flowers were collected late afternoon and hand pollination performed 18 h after collection. Fruit harvested as a result of the various pollen storage treatments varied significantly in weight, diameter, and the number of seeds per fruit. The pollen from ‘Lessard Thai’ sugar apple and ‘Gefner’ atemoya may be stored up to 24 and 48 h, respectively.