Docynia indica
| Son tra (Docynia indica) | |
|---|---|
| Scientific name | Docynia indica [1] |
| Common names | Son tra, H'mong apple, Assam apple, wild apple [2] |
| Genus | Docynia [1] |
| Family | Rosaceae [2] |
| Order | Rosales [1] |
| Native setting | Central and East Asian highlands, about 1000–3000 m [2] |
| Habit | Semievergreen or deciduous tree [2] |
| Fruit uses | Juice, wine, vinegar, syrup, jam and dried preserves [2] |
Docynia indica is a highland fruit tree of the rose family, widely known in northwest Vietnam as son tra or H'mong apple. The current taxonomic record treats Malus indica as a synonym. [1]
Description[edit | edit source]
The tree is semievergreen or deciduous and occurs naturally in Central and East Asian highlands at approximately 1000–3000 m. The species description associates fruiting with elevations above 1000 m and cold winters, and records occurrence on sloping or degraded ground. [2]
Son tra fruit is used fresh and in processed products including juice, wine, vinegar, syrup, jam and dried preserves. A species-specific descriptor protocol evaluates ripe fruit by colour, shape, skin texture, dimensions, weight, taste and juice content; its standard observations use 30 ripe fruits. [2]
Cultivation[edit | edit source]
Soil and water[edit | edit source]
The documented upland and sloping habitat supports a practical starting point of free-draining ground, such as a slope or raised planting area, rather than persistently wet soil. This is a habitat-based inference, not a measured species-specific soil or irrigation requirement. [2]
In northwest Vietnam, son tra has also been planted in hillside agroforestry systems with maize and forage grasses. That system context shows a documented field use, not a universal spacing, fertility or water schedule for the species. [4] [5]
Sun and humidity[edit | edit source]
Docynia indica is associated with cool, elevated environments rather than a lowland tropical setting. Give a planting good air movement and monitor its response to the local combination of sun, humidity and winter cold; the documented highland range should not be treated as a guaranteed hardiness limit. [2]
Seasonal changes[edit | edit source]
The species description links fruiting with cold winters and elevations above 1000 m. In the northwest Vietnam nursery protocol, fruit was collected from selected mother trees in September–November, while scion wood was collected in January–March. Those calendar windows belong to that project setting and should not be transferred unchanged to another climate. [2] [3]
Propagation[edit | edit source]
A northwest Vietnam nursery manual describes both seedling production and grafting. It instructs collecting fruit from selected mother trees in September–November, extracting the seed promptly, washing it, shade-drying it and soaking it in warm water for eight hours. The stated nursery mixture is 89% topsoil, 10% composted manure and 1% NPK, with 75% shade; watering is adjusted during the first 30 days and the subsequent nursery period. These are project instructions, not a controlled comparison of propagation methods. [3]
The same manual describes seedlings as ready for grafting at 12–14 months when they are about 0.8–1 m tall with a basal diameter of 0.6–0.8 cm. Scion wood is selected from productive, healthy mother trees in January–March, with at least two dormant buds, and is matched to a similarly sized rootstock. Grafted plants are acclimatized by removing shade one month before planting. [3]
Flowering, fruiting, and harvest[edit | edit source]
For fruit characterization, useful harvest records include colour, shape, skin texture, size, weight, taste and juice content. The descriptor protocol specifies observations from 30 ripe fruits, providing a consistent way to compare trees at one site without treating one tree's measurements as a species-wide range. [2]
Fruiting is associated with elevations above 1000 m and cold winters. Local flowering and harvest timing should therefore be recorded with the site's elevation and seasonal conditions rather than copied from a different climate. [2]
Fruit and uses[edit | edit source]
The fruit is processed into juice, wine, vinegar, syrup, jam and dried preserves. The descriptor framework also records taste and juice content, so those traits can be kept with harvest measurements when selecting trees for fresh or processed use. [2]
Agroforestry context[edit | edit source]
In northwest Vietnam, son tra has been used on hillsides with maize and grass crops. An institutional field account describes the fruit trees as part of farmer-adopted systems and as a source of cash, while a later assessment covers son tra–grass systems on farms in the region. These reports describe a regional agroforestry context, not guaranteed profitability or compatibility in every planting. [4] [5]