In Vitro Rooting of Arachis Paraguariensis On Agar Medium.

Plant tissue culture is a major foundation on which almost all research relating to plant biotechnology rests. Therefore, the importance of being able to successfully regenerate plants in vitro through tissue culture cannot be overemphasized. The wild peanut species Arachis paraguariensis Chodat & Hassl. (Section Erectoides) possesses very high frequency of in vitro shoot formation, and the ability to regenerate efficiently from protoplast and callus cultures. The high morphogenic potential displayed by this species supports its suitability as an ideal model system for studying in vitro regeneration and morphogenesis of leguminous species.  But failure of regenerated shoots to produce roots either in vitro or ex vitro have constituted a major limitation to the production of large numbers of surviving plantlets.  Rooting of six genotypes of A. paraguariensis on semi-solid MS medium that was supplemented with three different auxins at various concentrations were compared in 11.4 cm × 8.6 cm × 10.2 cm polyethylene terepthalate glycol (PETG) vessels and in 2.5 cm × 15 cm glass tubes. After 6 weeks of culture, plantlets in the wide PETG vessel showed a significantly higher rooting percentage, number of roots per plantlet and survival at acclimatization across all the auxin treatments than those in glass tubes.  Rooting response varied for each genotype while the best overall rooting performance was observed in shoots cultured on hormone-free MS medium. The results demonstrated how the size of tissue culture vessel, and the type and concentration of auxin in the nutrient medium influenced in vitro rooting of A. paraguariensis.