Pseudo-xenic Effect of Allied Annona spp. Pollen in Hand Pollination of cv. ‘Arka Sahan’ [(A. cherimola × A. squamosa) × A. squamosa]

Abstract

Annonaceous fruits are characterized by a serious problem of fruit set, and hand pollination is commonly practiced for improving the set. Because we observed that allied Annona spp. are freely crossable and often produce attractive Fo fruits, the possibility of using their pollen in hand pollination was investigated. A total of 1080 flowers of cv. Arka Sahan in 2003 and 3420 in 2004 were pollinated with A. atemoya Hort., A. cherimola Mill., A. reticulata L., A. squamosa L., and self-pollen. Pollen source had significant effects in both or either year on all 14 fruit traits studied except days to ripening. A. squamosa pollen gave the highest fruit set (greater than 91%) and the heaviest fruits (greater than 600 g). Good to moderate fruit set was recorded with A. reticulata and self-pollen (31% to 86%); and with A. atemoya and A. cherimola pollen, the set was poor (4% to 13%), whereas natural set was as low as 2%. ‘Arka Sahan’ fruits resulting from A. squamosa pollen showed quicker fruit maturity (128 days) and least weight loss on ripening (13%). Evaluation of fruit pulp quality revealed that pollen source and year had significant effects on the total soluble solids and acidity but not their ratio. Mean number of seeds per 100 g fruit was found to vary (6 to 11) with pollen source used. A. squamosa and A. reticulata pollen had higher seed count with good to moderate fruit size and symmetrical shape, but those from the rest of the pollen sources neither possessed good size nor shape. Results clearly showed that ‘Arka Sahan’ could be successfully hand pollinated with A. squamosa pollen. The differential ability of pollen sources to fertilize number of ovules and set seeds per fruit rather than the pollen genotype had a significant effect on many fruit traits like size, symmetry, skin thickness, and total soluble solids, which we describe as ”pseudo-xenia.” Useful pseudo-xenic effect is worth exploiting in fruit culture.