Macro propagation technique for rapid multiplication of Banana
Authors: Thejangulie Angami, Rupankar Bhagawati, S. R. Assumi
Banana is an important staple and a source of income for small holding growers of the tropical humid lowlands to dry mild subtropics of India. The fact that, banana fruits throughout the year add to its importance as a food security crop. However, the productivity and lifespan of banana has drastically reduced due to lack of proper scientific cultivation practices, inadequate high quality seedlings, pest and disease pressures, etc. These problems are escalating because farmers usually rely on natural regeneration of plants for the supply of planting materials, which are contaminated by pests and diseases and the available seedling production methods has failed to meet the high seedling demands.
Banana can now be successfully propagated aseptically through tissue culture technique, and the advantage of in vitro micro-propagation is that it eliminates all sucker-transmitted pests and diseases. However, tissue culture plants are not readily accessed by poor farmers, therefore in order to increase banana production in small scale system, there is a need for affordable and simple techniques for seedling production at the farm level. Macro-propagation, being a simple technology, will enhance banana production through rapid multiplication and timely delivery of sufficient high quality seedlings. This technique can greatly boost food security and income generation among small scale farmers if properly adopted for ensuring sustainability.
Macro-propagation is a relatively easy technique that can be carried out in shed or even in the open field. It consists of generating suckers from clean planting material by removing the apical dominance and includes:
1. Decapitation (False and complete decapitation)
2. Corm technique (Whole, Split and Excised corms)
In false decapitation, a small hole (~5 cm in diameter) is cut in the pseudostem of six month old plants to destroy the actively growing point i.e. the meristem. The hole is made at about 20 cm above the ground by removing the central part of the plant and the hole should slightly slope downwards, so that water and plant sap collect in the hole, further killing the meristem. In complete decapitation, the pseudostem of 6 month old plant is completely cut down at ground level, leaving out the emerging suckers. The meristem is destroyed by using a clean knife and removing 5 cm diameter growing part in the middle of the pseudostem. Usually, the meristem is soft and when hitting harder tissue (the corm), one can be sure the meristem is destroyed.
Both the plants from false and complete decapitation are left to stand for at least one month to allow sprouting. About 4 to 7 suckers, depending on banana cultivar, will sprout within three weeks after removal of the apical dominance. Sprouted suckers are detached immediately once they attain 3 to 4 leaves (usually when they measure 20-30 cm in height). Detached suckers are then transferred directly to the field.
2. Corm technique:
This technique is applied to harvested corms where the buds are present and the meristem is absent.
In Whole corm, roots are removed and the leaf sheets are cut one by one, exposing the buds. Fungicide may be applied. The corm is scarified at the top (by cutting an X). The entire corm is planted at 30 cm spacing in the propagator (constructed of bamboo and polythene sheet of 1.5 x 5.0 x 0.5 m size), well covered with sawdust and watered immediately after planting.
In Split corm, the corm is fragmented into two or more bits, depending on its size, and planted in the propagator for buds to sprout. Prepared corm pieces are planted at 10 cm interval and covered with 2 cm sawdust. The chamber is watering immediately after planting.
In Excised corm, buds are directly cut out from the corm in pieces of 50-100 g as minisets and planted in the propagator or polyethylene bags to sprout.
Macro-propagation provides an affordable, simple and relatively rapid technique for vegetative multiplication of banana which supported with the right training to farmers (mostly the low income, unskilled, small and medium scale farmers who are the major banana growers) have the potential to overcome challenges faced by farmers like increasing unavailability of seedlings at farm level with the assurance of affordable, quality, true to type and choice of cultivar seedlings to farmers.
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About Author / Additional Info:
The author is presently working as a scientist (fruit science).
Engaged in production aspects of fruit crop