ISHS Acta Horticulturae 415: VIII International Asparagus Symposium
EFFECT OF GENOTYPE AND AUXIN ON DIRECT SOMATIC EMBRYOGENESIS FROM PROTOPLASTS DERIVED FROM EMBRYOGENIC SUSPENSION CULTURES OF ASPARAGUS OFFICINALIS L. |
| Authors: | R.A. May, K.C. Sink |
| Abstract:
Embryogenic callus from four asparagus genotypes (Jersey Giant 8, MD10, Rutgers 22, and 86SOM1) was initiated from micropropagated spears placed on semisolid LS medium containing 5 μM 2,4-D or 50 μM NAA. After three subcultures, such callus tissue was used to initiate cell suspensions in liquid medium of the same composition. The eight sets of suspensions were used as sources of protoplasts at two months of age and again at five months. Protoplasts were immobilized at 105/ml density in MS medium with 0.6% agarose and overlaid with liquid KM medium containing the same concentration of auxin as the corresponding donor suspension or no plant growth regulators (PGR's). There was a significant interaction between genotype, suspension PGR, and inclusion or exclusion of PGR's in the protoplast culture medium. First divisions were observed as soon as 3 days depending on the culture, and plating efficiencies recorded at 14 days ranged from 0 – 40%. Globular somatic embryos developed directly from protoplasts at 10 – 14 days and bipolar embryos could be subcultured 3 – 4 weeks after initial protoplast culture. All four genotypes were capable of regenerating plants via protoplast-derived embryos; however, the best treatment involved protoplasts cultured without PGR's derived from 2-month old NAA suspensions of Rutgers 22, in which over 40% of the protoplast-derived embryos germinated into plants. | |
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