OPTIMASI MEDIUM PERBANYAKAN IN VITRO TUNAS TALAS KALIURANG (Colocasia esculenta L.) DIPLOID DAN TETRAPLOID

Taro cv. Kaliurang has a good taste and is tolerant to certain pests and diseases but its development is hampered by insufficient number of good quality plant materials. Quality improvement has been carried out through polyploidization. Shoot multiplication is an important step in micropropagation, which often needs specific formulation of culture medium. This study aimed to obtain an optimum formulation of in vitro shoot-inducing medium of taro cv. Kaliurang. Explants from one diploid and three tretraploid clones were subjected to six treatments of medium formulations with various concentrations of thiamine and adenine in BAP-containing MS media. Shoots were then rooted, followed by plantlet acclimatization. Ploidy level was measured using flow cytrometry. The rooting medium was 1⁄2 MS without growth hormones, whereas acclimatization medium was a mixture of sterile soil, husk, and cocopeat. The results showed that MS + 2 mg L BAP + 4 mg L thiamine + 2 mg L adenine was the optimum medium with an average 3.45 shoots per explant. Plantlet acclimatization was successful with 99.1% survival. Flow cytometry measurement confirmed tetraploidy level of the regenerants from 3 tetraploid clones.