Tapioca-a new and cheaper alternative to agar for direct in vitro shoot regeneration and microtuber production from nodal cultures of potato.

Abstract

The efficiency of in vitro shoot regeneration and microtuber production of potato (Solanum tuberosum L.) from nodal explants was studied using agar and other new and cheaper gelling agents- tapioca and sago in Murashige & Skoog (MS) salt medium. For shoot regeneration, agar was maintained at 8 mg l -1, tapioca and sago were varied between 9-18 and 10-14 % (w/v), respectively supplemented with 3% sucrose, 0.03 mg l-1 NAA, 0.25 mg l-1 GA3 and 2.5 mg l-1 Ca-panthothnate. The microtuberisation study was done using agar, tapioca and sago at 0.8, 14 and 10% concentration (w/v), respectively, in the presence of benzylaminopurine and paclobutrazol. Type of gelling agent significantly affected in vitro plant regeneration. After 32 days, shoot height and number of nodes respectively were 8.86 cm and 10.5 in agar, and 8.9 -12.1 in 11-15% tapioca, respectively. Tapioca at 14-15% stimulated growth giving significantly (P<0.01) higher root fresh weight gain (36.3%) over agar. Microtuber fresh weight was influenced more by the type of gelling agent than microtuber number. The highest (53.3%) biomass conversion was found with sago in the medium containing paclobutrazol followed by agar (43.3%) in BAP medium. A deferential increase in weight occurred in media solidified with tapioca and sago. Within 11-14% of tapioca, the existence of a favourable osmotic environment and better carbohydrate and/ or ionic supplement to the culture medium than agar is suspected causing improved cell growth and morphogenesis. The result showed the possibility of a successful use of tapioca, a cheaper gelling substance, for in vitro culture of potato.

Key Words: Microtubers, sago, shoot regeneration, Solanum tuberosum, tapioca, tissue culture African


(African Crop Science Journal 2001 9(1): 1-8)