Tamarillo
The tamarillo is a tree or shrub in the flowering plant family Solanaceae. It bears an egg-shaped edible fruit. It is common globally, especially in its native South America, and has been introduced in New Zealand, Nepal, Rwanda, Burundi, the Democratic Republic of the Congo, Australia, and Bhutan.
Origin and regions of cultivation
The tamarillo or chilltu is native to the Andes of Peru, Ecuador, Bolivia, Colombia, Argentina and Chile. Today it is still cultivated in gardens and small orchards for local production, and it is one of the most popular fruits in these regions. Other regions of cultivation are the subtropical areas throughout the world, such as Ethiopia, Burundi, Kenya, Rwanda, South Africa, Nepal, Hong Kong, China, Pakistan, the United States, Australia, Bhutan, New Zealand and Nagaland, Manipur, Darjeeling and Sikkim in India. It has also been seen in Cantabria, a province in Spain.Tamarillos were first introduced to New Zealand in 1891, from seeds originating from India. The plant, then known as the tree tomato, was popularly grown in home gardens, and small-scale commercial production began by the 1910s. Production peaked in New Zealand in the mid-1960s, declining in the 1970s onwards due to disease-related problems.
The tamarillo is a fruit harvested permanently in Colombia, the average annual production exceeds 150,000 tons. Antioquia has the largest number of hectares planted with La Meseta being the place where more than 900 hectares are located and from which the main cities of the country are supplied.
In 1993, in New Zealand, about 2,000 tons were produced on 200 hectares of land and exported to the United States. By 2020, there was a decrease from 150 after the discovery of the tomato potato psyllid in 2006. This was reflected in a corresponding reduction in volume from 800 tonnes worth $3.5 million, to 250 tonnes valued at $1.3 million at that time. In 2021, growers sold 414 tonnes through the domestic wholesalers at a value of $3.1 million, and 8 tonnes exported to the USA from two growers at a value of $0.02 million. For the export, the existing marketing channels developed for the kiwifruit are used.
The first internationally marketed crop of tamarillos in Australia was produced around 1996.
The tamarillo is also successfully grown at higher elevations of Malaysia and the Philippines, Ethiopia and in Puerto Rico. In the hot tropical lowlands, it develops only small fruits and fruit setting is seldom.
In Pakistan, tamarillo is cultivated on a limited experimental scale, mainly in cooler high-altitude regions such as Azad Kashmir and parts of northern Punjab.
Naming
In 1966, the New Zealand Tree Tomato Promotions Council sought to coin a new name for the fruit, after growers suspected that the name 'tree tomato' was hindering export market potential for the crop, due to confusion around how the fruit was eaten and how similar it was to garden tomatoes. The council found none of the pre-existing names across South America to be suitable, wanting a name that sounded subtropical, appealing, and easy to pronounce and spell in different languages. The name tamarillo was proposed as a sort of pseudo-Hispanicism influenced by the name of the crop tomatillo, but with an added Māori element after Tama-te-kapua, captain of the Arawa migration canoe. Growers overwhelmingly voted for the change, and from February 1967 the name came into wide usage across New Zealand. The name 'tamarillo' is not universally used, and this plant has a different name in many regions.It is also known as the tree tomato, tomate de árbol, tomate andino, tomate serrano, blood fruit, poor man's tomato, tomate de yuca, tomate de españa, sachatomate, berenjena, chilto and tamamoro in South America, tyamtar, rambheda or rukh tamatar in Nepal, and terong Belanda in Indonesia.
Plant description
The plant is a fast-growing tree that grows up to 5 metres. Peak production is reached after 4 years, and the life expectancy is about 5 to 12 years. The tree usually forms a single upright trunk with lateral branches. The flowers and fruits hang from the lateral branches. The leaves are large, simple and perennial, and have a strong pungent smell. The flowers are pink-white, and form clusters of 10 to 50 flowers. They produce 1 to 6 fruits per cluster. Plants can set fruit without cross-pollination, but the flowers are fragrant and attract insects. Cross-pollination seems to improve fruit set. The roots are shallow and not very pronounced, therefore the plant is not tolerant of drought stress and can be damaged by strong winds. Tamarillos will hybridize with many other solanaceae, though the hybrid fruits will be sterile, and unpalatable in some instances.Fruit
The fruits are egg-shaped and about 4-10 centimeters long. Their color varies from yellow and orange to red and almost purple. Sometimes they have dark, longitudinal stripes. Red fruits are more sour, yellow and orange fruits are sweeter. The flesh has a firm texture and contains more and larger seeds than a common tomato. The fruits are very high in vitamins and iron and low in calories.| Component | Range | Component | Range |
| Water content | 81–87 | Vitamin A | 0.32–1.48 |
| Proteins | 1.5–2.5 | Vitamin C | 19.7–57.8 |
| Fat | 0.05–1.28 | Calcium | 3.9–11.3 |
| Fiber | 1.4–6.0 | Magnesium | 19.7–22.3 |
| Total acidity | 1.0–2.4 | Iron | 0.4–0.94 |
Cultivation
Soil and climate requirements
The tamarillo prefers a subtropical climate, with rainfall between 600 and 4000 millimeters and annual temperatures between 15 and 20 °C. It is intolerant to frost and drought stress. It is assumed that fruit set is affected by night temperatures. Areas where citrus are cultivated provide good conditions for tamarillos as well, such as in the Mediterranean climate.Tamarillo plants grow best in light, deep, fertile soils, although they are not very demanding. However, soils must be permeable since the plants are not tolerant of water-logging. They grow naturally on soils with a pH of 5 to 8.5.
Growth
is possible by both using seeds or cuttings. Seedlings first develop a straight, about 1.5 to 1.8 meters tall trunk, before they branch out. Propagation by seeds is easy and ideal in protected environments. However, in orchards with different cultivars, cross-pollination will occur and characteristics of the cultivars get mixed up. Seedlings should be kept in the nursery until they reach a height of 1 to 1.5 metres as they are very frost-sensitive.Plants grown from cuttings branch out earlier and result in more shrub-like plants that are more suitable for exposed sites. Cuttings should be made from basal and aerial shoots, and should be free of pathogenic viruses. Plants grown from cuttings should be kept in the nursery until they reach a height of 0.5 to 1 meter.
The tree grows very quickly and is able to bear fruit after 1.5 to 2 years. The plant is daylength-insensitive. The fruits do not mature simultaneously, unless the tree has been pruned. A single tree can produce more than 20 kg of fruit per year; an orchard yields in 15 to 17 tons per hectare. One single mature tree in good soil will bear more fruit than a typical family can eat in about 3 months.
Tamarillos are suitable for growing as indoor container plants, though their swift growth, their light, water and humidity requirements and their large leaves can pose a challenge to those with limited space.
Plant management
The tamarillo trees are adaptable and very easy to grow. However, some plant management strategies can help to stabilize and improve plant performance.Planting
Planting distances depend on the growing system. In New Zealand, with mechanized production, single row planting distances of 1 to 1.5 metres between plants and 4.5 to 5 metres between rows are recommended. In traditional growing regions such as the Andean region, plantations are much more dense, with 1.2 to 1.5 metres between plants. Dense planting can be a strategy to protect plants against wind. On poorly drained soils, plants should be planted on ridges.Pruning
can help to control fruit size, plant size, harvest date and to simplify the harvesting of fruits. Cutting the tip of young plants leads to the desired branch height. Once the tree shape has been formed, pruning is reduced to the removal of old or dead wood and previously fruited branches, since branches that have already carried fruits will produce smaller fruits with lower quality the next time. Light pruning leads to medium-sized, heavy pruning to large-sized fruits. Basal shoots should be removed. When plants are grown in greenhouses, pruning prevents excessive vegetative growth.When the tree is about 1 to 1.5 metres in height, it is advisable to cut the roots on one side and lean the tree to the other. This allows fruiting branches to grow all along the trunk rather than just at the top.