Effect of Kinetin on Organ Formation in Callus Tissue Derived from Rice Embryos

Effect of kinetin on organ formation in rice callus tissue was studied using Maede's medium containing yeast extract, vitamines and 2, 4-D. The following results were obtained. (1) When kinetin was added in to the medium containing 2, 4-D at 10-7M, shoot formation in callus was promoted as concentration of kinetin increased. Root formation was not influenced by addition of kinetin. (2) Shoot-like protuberances appeared in callus tissues at 10 to 14 days after transfer of callus in to the test medium. Numerous protuberances did not make any growth, and they turned to be necrosis for 30 days after the transfer. Few protuberances developed to normal shoots, while a half of the shoots were albino. (3) Varietal difference was not observed in the effect of kinetin on shoot formation in the callus tissues of various varieties, which are Te-Tep, Norin-8, Norin-29, Kyoto-asahi and Tan-ginbozu. (4) It is necessary for acceleration of kinetin action to contain yeast extract and/or casein hydrolysate in the medium. Adenine failed to exert any effect on shoot regeneration in callus tissues.