A one step in vitro cloning procedure for Red Globe grape: The infuence of basal media and plant growth regulators

Earlier studies have shown that the degree of success at each stage of micropropagation in grapevine is genotype dependent; hence it becomes imperative to optimize culture conditions for rapid propagation of a variety. Present report describes two approaches of in vitro propagation of a Vitis vinifera cultivar, Red Globe. In one approach, whole plants could be developed from single node segments by bud break and direct rooting in vitro. Eight different basal media tried showed different morphogenetic responses. In second approach, multiple shoots were induced in nodal segments cultured on MS basal medium supplemented with BA (8.88 µM). Also, second crop of shoots could be induced in left over nodal segments devoid of shoots. Rooting of shoots could be induced in vitro, both in semi-solid or liquid media and also ex vitro by pulse treatment of IAA (2.85 µM) + NAA (2.70 µM). Plant establishment in later case was 80%. A simple procedure described here can complement conventional methods, currently being used in propagation of this important grape variety. solution for 10 min and rinsed three times with sterile water. The explants were finally blotted dry on sterile filter paper and inoculated on medium in glass test tubes (150 X 25 mm). For budbreak, eight different basal media-MS (Murashige and Skoog, 1962), WPM (Lloyd and McCown, 1980), NN (Nitsch and Nitsch, 1969), B5 (Gamborg et al., 1968), ER (Eriksson, 1965), LS (Linsmaier and Skoog, 1965), C 2 d (Chee and Pool, 1987) and GNMG (Galzy et al., 1990) devoid of growth regulators were tested. Another experiment with MS medium and range of BA concentrations (0.04 to 11.1 µM) was undertaken to maximize budbreak. To obtain second crop of shoots, primary nodal segments left after excising the grown axillary shoot (hereinafter referred to as mother explant) instead of its discard, were transferred to WPM or MS with or without BA (4.44 and 8.88 µM). For induction of multiple shoots, axillary shoots obtained from primary nodal segments were inoculated (S0) in test tubes having MS medium with BA (2.22 to 8.88 µM). After 30 d, explants showing multiple shoots were transferred to fresh medium in glass bottles. This was continued at an interval of 30 d until five transfers (from S1 to S5). To test the effect of inoculum's density per culture vessel, two, three, four or five shoot clumps per culture bottle were inoculated on MS with BA at 4.44 or 8.88 µM. Two sets of experiments were carried out for elongation of in vitro shoots. In the first set, shoots less than 3 cm in length were inoculated on WPM supplemented with or without BA (2.22-8.88 µM). In the second set, multiple shoot clumps with shoots of <1.5 cm in length were kept for elongation. These were inoculated in glass bottles containing MS supplemented with BA (2.22 or 4.44 µM) and NAA (0.54 µM). For in vitro rooting, shoots more than 3 cm were inoculated in test tubes containing half or full strength MS or WPM supplemented