Preliminary studies on direct plant regeneration from stem segments of pummelo (Citrus grandis) cv. Melomas

A direct plant regeneration system for Citrus grandis cv. Melomas was established using stem segments of one-month-old in vitro seedlings. Multiple shoots were proliferated on Murashige and Skoog (MS) medium supplemented with 6-(gamma, gamma-Dimethylallylamino) purine (2-ip) and indole-3-acetic acid (IAA). The highest number of shoots, 6 shoots per explant were produced on medium containing 1 mg/litre each of 2-ip and IAA. Roots developed well when regenerated shoots were excised and cultured on half strength MS medium supplemented with naphthaleneacetic acid (NAA). The highest rooting percentage was produced on MS medium supplemented with 0.1 mg/litre NAA and the highest number of roots per plantlet was produced on MS medium supplemented with 1 mg/litre NAA. In vitro pummelo plantlets exhibited normal growth in soil under greenhouse conditions.