A COMPARATIVE-STUDY ON MODE OF CULTURE AND PLANT-REGENERATION FROM PROTOPLAST-DERIVED SOMATIC EMBRYOS OF 2 GENOTYPES OF ASPARAGUS-OFFICINALIS L

The plating efficiency of protoplasts derived from embryogenic callus of two genotypes of Asparagus officinalis L. differed with different protoplast culture media, culture modes, plating densities and carbon sources. Likewise, the two genotypes varied in their responses to these different conditions. Protoplasts grew best in a semisolid medium at 1 x 10(5) protoplasts/ml in half strength Murashige and Skoog's medium (MS) supplemented with 1 mg/l NAA, 0.5 mg/l zeatin, 0.6 M glucose and 0.1% (w/v) Gelrite. The plating efficiencies were 12.5% and 8.1% for genotypes G-203 and G-171, respectively. The protoplast-derived microcolonies and microcalli were cultured on solid MS medium containing 1 mg/l 2,4-D, 3% (w/v) sucrose and 0.2% (w/v) Gelrite to obtain embryogenic calli. Plantlets developed following somatic embryogenesis. The somatic embryos were matured and then germinated to plantlets in EMM, MS medium with 0.1 mg/l NAA, 0.3 mg/l 2-isopentenyladenine and different carbohydrates. Transfer of somatic embryos from EMM with 10% glucose to EMM containing 2% sucrose gave the highest number of mature bipolar embryos and plantlets for both genotypes.