‘Duncan’, of unknown parentage, was one of the few patented varieties of Florida, being bred and protected by David Sturrock of Palm Beach County due to its exceptional production, disease resistance and eating quality. The fruit are oblong and are of uniform shape throughout the canopy, from 16 to 24 oz with an average size of 550 g (19.5 oz). The color is a solid canary yellow with no blush. The skin is thick, waxy and resistant to handling damage, with a soft, tender, and juicy orange flesh. The flesh is velvet-smooth and bright yellow, with an exceptionally sweet, slightly tangy, refreshing flavor reminiscent of ‘Carabao’, with a hint of citrus and a fruity aroma. The fruit ripen in July in Florida and are tolerant of anthracnose infection, making them suitable for production under humid, rainy conditions. Production is heavy. The tree itself is vigorous and open in its growth habit, but highly manageable. It can be maintained at a height and spread of 8 to 10 ft with a minimal of care and pruning.

Source: http://www.virtualherbarium.org/tropicalfruit/mangotrees.html