Nam Doc Mai - Si Thong / Sia Tong

The Nam Doc Mai Si Thong, popularly nicknamed the Golden Nam Doc Mai, stands apart from its siblings in the Nam Doc Mai family through one striking feature — at full maturity, its skin develops a brilliant, sun-kissed golden-yellow hue, rather than the pale ivory or light green tone typical of other Nam Doc Mai selections.

The fruits are of moderate size, displaying the trademark elongated, S-shaped curve and tapering tip that mango enthusiasts immediately recognise as a Nam Doc Mai signature. However, they generally run a bit smaller than the fruits of Nam Doc Mai #4 and Nam Doc Mai Mun. Inside, the pulp is a soft pale-yellow shade, exceptionally fine-textured, almost silken on the palate, and carries the very same taste profile the variety is celebrated for — a honey-like (TSS: up to 20 brix), floral sweetness, free of any sharpness, sourness, or acidic edge. The stone within is slender, elongated, and produces multiple embryos, making it polyembryonic in nature.

When it comes to the tree itself, the Si Thong is not quite as early to bear as Nam Doc Mai #4 and shows somewhat stronger, more energetic growth. Even so, it rewards the grower with a healthy yield, and one of its practical advantages is that its fruits are far less prone to cracking or splitting than those of other Nam Doc Mai varieties.

The cultivar also demonstrates a good degree of resistance to common diseases. In West Bengal, India, it behaves as a mid-season variety, with fruits typically reaching ripeness from the initial days of June and continuing through the first week of July in most seasons. The trees themselves grow with moderate vigour and form a thick, upward-reaching canopy of dense foliage.

ColourBright YellowAverage Weight300 gramsSweetnessTSS up to 20 BrixPulp Recovery75%Shelf Life8-10 daysSeed TypeBig and polyembryonicBearingIrregular and shy bearer