An Efficient in vitro Regeneration System for Australian-Grown Chickpea (Cicer arietinum) Cultivars

Abstract

A comparison of methods for efficient in vitro regeneration of Australian-grown chickpea (Cicer arietinum L.) cultivars was undertaken. The most efficient regeneration system was one where immature cotyledon and embryonic axis explants, 14-21 days post-pollination, were cultivated on Murashige and Skoog's salts with Gamborg's vitamins, 1.0, 3.0 or 5.2 mg L^-1 zeatin, 0 or 35 μg L^-1 indole-3-acetic acid, 30 g L^-1 sucrose and 8 g L^-1 Phytagar. The first embryoid structures appeared after 2 weeks of culture at 25 ± 1°C in dim light (150 μmol m^-2 s^-1) and formed directly on the edges of the immature cotyledons or petiole stumps. Between 10 and 20 structures were produced on each cotyledon explant in two cultivars, however, the embryogenic structures which developed on cv. Narayen were more efficiently transformed into shoots than far cv. Amethyst. An efficient regeneration medium (2 mg L^-1 naphthaleneacetic acid, 1/2 Murashige and Skoog's salts with Gamborg's vitamins, and 0.5 g L^-1 activated charcoal) was used to develop a portion of the shoots into morphologically normal plants growing in a vermiculite and soil potting mix in a growth room. Less efficient in vitro regeneration was observed when hypocotyl and shoot sections, and shoot apices were induced to form callus and plants by organogenesis. These plants could not be established in a potting mix. The amount and type of callus produced varied between explant type and cultivar.