An improved micropropagation system, ex vitro rooting and validation of genetic homogeneity in wild female Momordica dioica: an underutilized nutraceutical vegetable crop

Momordica dioica Roxb. ex Willd., is a perennial and dioecious (2n = 28) plant of family Cucurbitaceae. Conventional methods of propagation through seeds, stem cuttings and rhizomatous/tuberous roots are inadequate for its mass cultivation as a vegetable crop. This paper reports an improved and efficient micropropagation method for wild female M. dioica using nodal explants. Shoot amplification was achieved using subculturing of in vitro raised shoots on MS medium supplemented with various concentrations of 6-benzylaminopurine (BAP) alone or in combination with indole-3-acetic acid (IAA). The maximum number of shoots (45.30 +/- 3.83) with an average length 6.52 +/- 0.89 cm were differentiated on MS medium containing 0.5 mg L-1 BAP, 0.1 mg L-1 IAA and additives (50 mg L-1 ascorbic acid, 25 mg L-1 each of adenine sulphate, citric acid and l-arginine). The cloned shoots were rooted ex vitro. Each shoot treated with 250 mg L-1 IBA for 5 min produced 12.3 +/- 1.33 with a mean length 5.4 +/- 0.73 cm. More than 85% (46 plants) of ex vitro rooted plantlets were successfully hardened in a greenhouse with normal growth characteristics. In order to evaluate the genetic stability of micropropagated plants, the two PCR-based techniques, Random Amplified Polymorphic DNA (RAPD) and Inter Simple Sequence Repeats (ISSR) were used. The amplification patterns of the micropropagated and mother plant were monomorphic thus depicting genetic stability of the micropropagation system. This protocol could be effectively employed for the mass multiplication of wild female M. dioica, a popular summer vegetable crop.