Siam Villa Garden: Thai Purple Mango

The Nam Doc Mai mango variety originated in Thailand and was introduced to Australia in the early 1980s. In Thailand, Nam Doc Mai is the most popular mango variety and generally eaten when soft ripe. It is a major variety of commerce in Asia. In Australia, it is eaten both as a ripe fruit and hard green fruit in Asian recipes.

The fruit quality is excellent, with a pale green/yellow fibreless flesh and a rich, sweet flavour. Nam Doc Mai is grown commercially in many Australian mango-growing districts, but is a minor variety in the Australian market.

Tree characteristics

The Nam Doc Mai tree is of medium-to-high vigour with an upright, dense canopy. The newly emerging leaves are initially light green, turn tan as they expand and become dark green as they mature. The leaves have a characteristic wavy edge. Six-year-old trees can reach heights of 6 m or more and a diameter of 4-6 m if left unpruned.

Flowering characteristics

panicle length - 30-40 cm

panicle width - 20-30 cm

hair density - medium

colour - faint pink

colour of wilted petals – brown.

Fruit characteristics

fruit shape - elongate slightly sigmoid

ground colour - green/yellow

blush colour - faint pink

average weight - 250-400 g (avg 340 g)

average length - 130 mm

average width - 61 mm

average depth - 71 mm

lenticel size - small

lenticel colour - yellow/white

flesh colour - green/yellow

skin thickness - thin

flesh fibre - low to none

firmness - medium to soft

stem end shape - elevated

beak shape - prominent

flesh recovery - 75 per cent

flavour - mild and very sweet

embryo type – polyembryonic.

Propagation

Nam Doc Mai is a polyembryonic* mango and when planted, the seed will produce several seedlings most of which will produce fruit that is true to type. Trees propagated by grafting will come into production earlier, producing fruit 1-2 years after planting. Seedlings can take up to 5 years to fruit.

* Refer to Glossary

Plant density

Although the Nam Doc Mai tree is of medium-to-high vigour, its upright branch habit allows it to be planted at closer spacings than Kensington Pride. Recommended spacings are 4-6 m in the row and 9 m between rows (185-278 trees/hectare). Closer plantings can be managed, though they require heavy annual pruning to maintain a smaller canopy size.

Pruning and shaping

During the first few years after planting, branches should be tipped after every second flush to encourage the canopy to spread and develop a well-branched frame capable of holding heavy crops in later years. When the tree begins to bear fruit, an annual thinning of the canopy is necessary to reduce foliage density. Dense canopies harbour pests and prevent spray penetration. Topping to keep the tree at a height of 3-5 m and skirting to remove low branches for under tree access should also be carried out annually.

Flowering and fruit set

Nam Doc Mai is a strong, regularly flowering tree in most Australian growing regions. However, in some years, fruit set is a problem and nubbins (fruit without seed) may be produced. Nubbins are either shed during late fruit development or, if held full term, develop to half or three-quarters the size of seeded fruit. Nam Doc Mai is an irregular bearer and tree yields vary greatly from year to year.