PRODUCTION OF MICROTUBERS IN POTATO (SOLANUM TUBEROSUM L.)

BEYAZOVA, Sevgi

M.Sc., Department of Biology

Supervisor: Assoc. Prof. Dr. Hüseyin Avni Öktem

January 1999, 70 pages  

Potato (Solanum tuberosum L.) is one of the major food sources and is being cultivated in all parts of Turkey. Potato is produced vegetatively by using seed tubers, which should be true to type and free of diseases.

Recent studies demonstrate the potential use of microtubers as seed tubers. Microtuber is an alternative end product of micropropagation, produced by allowing in vitro plantlets to grow under tuber inducing conditions.

In the present study microtuberization potential of three potato cultivars (Ausonia, Granola, Marfona) that are commonly cultivated in Turkey were investigated. Among the studied microtuberization systems, two-phase solid propagation-liquid tuber induction system was found to be the best yielding system. This system yielded microtubers with average weights of 192, 92 and 82 mg and average number of microtubers per tube were 2, 3 and 1 for cvs Ausonia, Granola and Marfona, respectively. Addition of charcoal significantly (p<0.05) increased the weight of microtubers (310, 132 and 111 mg for cvs Ausonia, Granola and Marfona, respectively) where number of microtubers per tube was not affected. Except cv Marfona, most of the microtubers retained 80% of their fresh weight after eight weeks of storage at 4°C or 20°C. Storage temperature and time were found to influence the sprouting ability of the microtubers. At 4°C, after 16 weeks of storage, 48, 44 and 0% of microtubers of cvs Ausonia, Granola and Marfona were sprouted, respectively, whereas at 20°C after 12 weeks, for the same cultivars the sprouting percentages were 100, 29 and 19%. Sprouted microtubers were found to be suitable for both in vitro culturing and direct cultivation in soil.

In conclusion, with respect to weight and number of produced microtubers, the described two phase microtuber induction method seems to be one of the best yielding microtuberization systems described in literature.

Key words: Potato, in vitro tuberization, microtuber, two-phase induction system, charcoal.