Self-fertility and preferential cross-fertilization in mango (Mangifera indica)

Mango (Mangifera indica L.) is a tropical fruit tree originated from Southeastern Asia, which is cultivated worldwide in regions with tropical and subtropical climates. Mango cultivation area has significantly extended in the last decades often to regions where environmental conditions are not the most favourable for optimal mango flower development and fruit set and, consequently, several reproductive problems had been described in this species. Some of them could be related to self-incompatibility, but so far information is not clear on the possible self-incompatibility system operating in this crop. In this work we study pollen tube growth, following self and cross pollination, in three mango cultivars ('Osteen', 'Kent' and 'Kensington'). Paternity was also determined in the offspring of two of these cultivars - 'Osteen' and 'Kent' - and in a solid block of an additional cultivar, 'Keitt'. Sequential examination of pollen tube growth showed that pollen tubes grew to the base of the style in both cross- and self-pollinated pistils of the different cultivars examined. Paternity analysis of 'Osteen' and 'Keitt' offspring in monovarietal orchards showed the production of fruits resulting from self-fertilization in both cultivars. The results from the multivarietal orchard corroborate this fact for 'Osteen' and 'Kent', but showed a preference for outcrossing in 'Osteen'. Pollen tube behaviour and paternity analysis show self-fertility in this species but the higher proportion of fruits resulting from outcrossing suggests a preference for cross-fertilization.