Author
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SNEZANA, IVIC - 1275-25-00 |
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Smigocki, Anna |
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Submitted to: BARC Poster Day
Publication Type: Abstract Only Publication Acceptance Date: 3/22/2001 Publication Date: N/A Citation: N/A Interpretive Summary: Technical Abstract: Sugarbeets provide nearly 50% of the consumable sugar in the U.S. Sugar yields are reduced by about 30 to 100% by diseases and insect pests. Traditional breeding for resistance has not been successful because sugarbeet is highly heterozygous. Biotechnological improvement is nearly nonexistent because gene transfer methods are not reproducible or cultivar independent. A biolistic sugarbeet transformation method was developed in this laboratory using embryogenic hypocotyl callus of a tissue culture clone REL-1. REL-1 has high regeneration potential in vitro but is not suitable as a breeding line. We tested our transformation method with 5 commercial sugarbeet varieties. Hypocotyl and cotyledon callus growth and shoot regeneration were highest for line C69. Shoot regeneration potential was 5.5% from hypocotyls and 8.8% from cotyledons with an average of 4 regenerated shoots per explant. A new explant cultivation medium increased the number of hypocotyls with callus and shoots. The C69 callus was used in our transformation protocol that also included varying the kanamycin concentration and plant growth regulator composition in the selection media used for cultivation of bombarded callus. Some of these treatments improved the shoot regeneration rate, but most of the PCR positive transformants were vitrified and did not develop into normal plants. Since 9 to 12 weeks are required to produce the hypocotyl and cotyledon callus, leaves from greenhouse-grown plants were used as a source of callus. Of the 7 lines tested, line FC607 formed regenerative callus on 81% of the explants in 6 weeks. This callus may prove to be more effective for introducing beneficial genes into commercial sugarbeet varieties. |
