Investigation into low-cost medium for hardening of in vitro banana plantlets to promote adoption of disease-free plants.

摘要

With the reduction in both the price and quota of sugar for world export, sugarcane growers in Mauritius are shifting to large-scale banana plantation. As suckers from existing old plantations represent a high risk of Cosmopolites sordidus and viral disease transmission, the demand for disease-free, tissue-cultured banana plantlets is increasing. However, the price of such plantlets from commercial laboratories is too high (about 3-4 times more expensive than suckers) due to - among others - the reliance on imported potting mixes for the weaning of plantlets. With the objective of finding low-cost potting mixes for weaning, a trial was set up using soil and manure mix, locally available by-products from the sugar industry (scum, flyash and bagassse), cocopeat (after use from soil-less cultures) and imported jiffy pellets. After deflasking, banana plantlets (2.5 cm tall) of 'Petite Naine' (AAA, Cavendish) were placed in eleven different potting mixes: (1) Scum, (2) Flyash, (3) Flyash+Scum (2:3), (4) Bagasse+Flyash (1:1), (5) Flyash+Scum (1:1), (6) Flyash+Scum (3:2), (7) Flyash+Scum (7:3), (8) cocopeat, (9) jiffy pellets, (10) non-sterile soil+cow manure (1:1), and (11) autoclaved soil+cow manure (1:1). The plantlets were covered with transparent plastic cover to maintain humidity for 10 days. The number of dead plantlets, plantlet height and leaf emission were recorded. Mortality was negligible indicating that the non-sterile mixes did not cause any disease incidence. Plantlet development was fastest in sterile soil+manure mix and slowest in cocopeat and flyash/bagasse mixture. A low-cost option for weaning, which could reduce hardening costs by over 90%, was thus developed.