Abstract:
Papaya is an important economic fruit plant because its high demand for papaya fruit. Mass production of high-quality papaya seedlings is a crucial step in papaya cultivation. This research aimed to study the proper condition for shoot multiplication and root induction of papaya using plant tissue culture technique. The suitable sterile technique for papaya seeds was soaked with 250 ppm GA3 for 24 hours and sterilized with 4.5% NaOCl for 10 minutes. Then, sterilized seeds were cultured on ½ MS medium, which plants had the highest germination percentage. Next, the effects of nutrients and growth regulators on shoot multiplication and root induction of papaya TA151 cultivar and Khaek Dum cultivar were studied. Papaya TA151 cultivar had highest shoot multiplication when cultured with 0.5 MS and 1.0 MS medium, supplemented with 1.5% glucose. Moreover, the 1.5 MS medium, supplemented with 3.0% sucrose resulted in the highest shoot length. However, the medium modification, sugar and addition of FeNa-EDDHA had no effect on the growth of Khaek Dum cultivar. As for the study of plant growth regulators, it was found that 0.3 mg/l Thidiazuron (TDZ), supplemented with 0.1 mg/l 1- Naphthaleneacetic acid (NAA) was the most suitable medium for shoot multiplication of papaya TA151 cultivar. While shoot multiplication of Khaek Dum cultivar was MS medium supplemented with 6-Benzylaminopurine (BAP) at a concentration of 0.3 or 0.6 mg/l and 0.1 mg/l NAA. In addition, medium supplemented with only 0.6 mg/l kinetin resulted in a high shoot multiplication as well. As for root induction, papaya Khaek Dum cultivar had the highest number of roots and root length when cultured on MS medium supplemented with 0.6 mg/l NAA in light condition