Dokmai Dogma has treated several banana varieties and species earlier, and today we continue with the red banana Musa acuminata AAA ‘Red Dacca’ (‘gluay nak’, gluay dhaeng or ‘gluay krang’ in Thai).
The origin of ‘Red Dacca’, a sterile triploid selected by man, is obscure. Some say India, some say Central America (other vernacular names are ‘Red Cuban’ and ‘Banana Roxa’). ‘Red Dacca’ may mutate and lose the ability to make red pigments, and such cultivars are called ‘Green Dacca’. All wild banana species originate in east Asia and the wild ancestor of ‘Red Dacca’, Musa acuminata (AA) is native to Malaysia.
The leaf stalks, mid-ribs and base of the pseudostems are red too, making a fruit-less ‘Red Dacca’ plant easy to recognize in a banana collector’s orchard.
Unlike the ‘gluay nam wa’ banana which is widely grown in Thailand, the leaves of ‘Red Dacca’ are unsuitable for cooking, wrapping or serving. Until recently the Thai farmers had no cutlery, no chop sticks and no plates. They had to eat with their fingers and serve all food on banana leaves, and so the banana leaves had to be of superior quality. Poor quality leaves may in fact spoil food by contaminating it with unwanted flavours and bitterness. This is one of the reasons ‘Red Dacca’ is not that common in Thailand and is mostly sold at touristic food markets. Other reasons are the peel’s tendency to crack which indeed frequently occurs here at Dokmai Garden and there is a rumour it may cause skin problems. However, it seems much more popular in Burma where one name is ‘shwe nget-pyaw’. The fresh fruit is in fact delicious; its sweet flavour is nicely balanced with some acidity. The fruit can be used as a cooking banana too, although this is not a plantain (which contains Musa balbisiana genes AAB).
To our experience at Dokmai Garden, ‘Red Dacca’ is much more water demanding than ‘gluay nam wa’ and so it should be planted where you can provide some irrigation during the dry season. This is another reason Red Dacca is not common in the dry Chiang Mai valley.
Fruits of ‘Red Dacca’ may be more or less red, orange or maroon. Many people wonder about this high degree of colour variation. Red, blue and purple colours in leaves, petals and fruits are usually due to anthocyanins, but I have not found any literature with actual analyses of the ‘Red Dacca’ banana peel.
In banana plants anthocyanins normally only occur in high quantities in the banana flowering bracts, and the reason most plants seem to produce anthocyanins in petals and fruits is to attract insects for flower pollination and birds for seed dispersal. The red fruits of ‘Red Dacca’ is due to a mutation and being a sterile selection by man the colour has no selective importance or natural function, although one can argue it is an adaptation to man. Although the anthocyanin in ‘Red Dacca’ may not serve any purpose, the regulation of its concentration may still follow the same mechanisms as in plant tissues where it does play a role. The intensity of anthocyanin colour may depend on 1) fruit maturity, 2) degree of sun exposure, 3) temperature, 4) soil and 5) stress.
1) Red on green (immature fruit) makes the fruit look brownish, red on yellow (mature fruit) makes the fruit look more orange and red on brown (over-ripe fruit) makes a maroon colour.
2) Anthocyanin formation is normally induced by light, but too much solar radiation may destroy the molecule. For instance, the attractive red blotches of the leaves of Sumatran zebra banana (Musa acuminata ssp. zebrina) develop best in a somewhat shady environment, but fade in full sun.
3) Low temperature seems to increase anthocyanin formation although there is a complex correlation involving both solar radiation and temperature in combination. This also means you may experience various degrees of coloration depending on which season and altitude the bananas are formed. This article on anthocyanin formation in Merlot grapes is quite interesting.
4) Presence of metals (as a consequence of soil type) in the cell’s vacuoles where the pigment is located, may influence acidity which in turn influence the colour of the anthocyanin. Soils poor in certain nutrients, a type of stress, may also increase anthocyanin production in many plants.
5) Anthocyanins may play a role in osmotic adjustments (cellular water content regulation) caused by fungal infections, herbivores, nutrient deficiency and lack of rain. If the ‘Red Dacca’ fruits can produce anthocyanins then stress may increase the amount of pigment. An interesting observation is that red autumn colours in many leaves is a phenomenon typical of boreal and cold latitudes while a rare phenomenon here in the tropics. However, tropical plants often produce anthocyanins in young shoots which appear red or purple, probably as an adaptation to the strong solar intensity (like building a roof (anthocyanin) before installing the sensitive machinery (the green photosynthesis apparatus)). You can read more in this splendid review of (foliar) anthocyanins:
The yellow pigment of the flesh inside the fruit is due to carotenoids which can be transformed into vitamin A. That makes ‘Red Dacca’ a more valuable source of that vitamin than the cream-coloured flesh of the common Cavendish bananas.
Indeed we shall plant ‘Red Dacca’ suckers in various environments to study variation in colour.
Text & Photo: Eric Danell
Other Dokmai Dogma banana blogs: