Regeneration of soybean via embryogenic suspension culture

In an attempt to establish an alternative plant regeneration system for soybean [Glycine max (L.) Merrill] cultivars used in Brazilian breeding programs, ten genotypes were tested for their embryogenic potential. Cotyledons were removed as explants from immature seeds harvested from field-grown plants. After 45 days on induction medium, the number of responding cotyledons and the number of somatic embryos per immature cotyledon were evaluated. The percentage of explants that produced somatic embryos varied from 1 to 70% among cultivars. The average number of somatic embryos produced per cotyledon pair ranged from 0.01 to 10.3 with a mean of 3.4. Suspension cultures were initiated with three Agrobacterium tumefaciens susceptible cultivars. Suspensions were successfully developed from Bragg and IAS5 cultivars. The packed cell volume, in one-month growth, increased 8.1 fold for Bragg and 3.5 fold for IAS5 and the fresh weight increased 6.6 and 2.8 fold, respectively. The cultivars differed for the analysed parameters. All tissue from each cultivar was transferred to the maturation medium and subsequently to the germination medium. The germination frequency was 45.7 and 54.9% for Bragg and IAS5, respectively. Plants were gradually exposed to ambient humidity over one week and then planted in soil. All plants yielded seeds in the greenhouse.

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

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.