Development of Long-term Cell Suspension Cultures of Wild Tomato Species, Lycopersicon chilense Dun. as Regular Source of Protoplast: An Efficient Protoplast-to-Plant System"

Initiation of direct and indirect cell suspension cultures of L. chilense Dun. was confined to the origin of auxin in the culture medium. Direct cell suspensions were initiated in MSPI culture medium containing NAA while indirect suspensions were initiated in culture media UM and UMI containing 2,4-D. The growth of direct and indirect cell suspensions was distinguished by the growth rate and phenolic production. Direct suspensions have shown a continuous growth in growth curve studies (8 day) and recorded a significantly higher cell growth in comparison to two other indirect cell suspensions. In indirect suspensions, 2,4-D toxicity arose after 5 months of culture and as a consequence loss of vigour followed by phenolic browning occurred. Direct cell suspensions proved to be long-term cultures without any adverse effects of NAA on the growth rate and were genetically stable. Higher protoplast yields were obtained from the direct cell suspension cultures which were associated with the increased growth rate. A productive protoplast-to-plant system was developed.