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This article in CS

  1. Vol. 42 No. 4, p. 1303-1308
    Received: July 3, 2001

    * Corresponding author(s): pbregit@uidaho.edu
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Reduced Somaclonal Variation in Barley Is Associated with Culturing Highly Differentiated, Meristematic Tissues

  1. Phil Bregitzer *a,
  2. Shibo Zhangb,
  3. Myeong-Je Chob and
  4. Peggy G. Lemauxb
  1. a USDA-ARS, National Small Grains Germplasm Research Facility, 1691 S. 2700 W., Aberdeen, ID 83210, USA
    b Dep. of Plant and Microbial Biology, Univ. of California, Berkeley, CA 94720, USA


Modern plant breeding programs depend heavily on germplasm resources composed of closely related breeding lines and cultivars. Asexual introduction of recombinant DNA offers novel opportunities for crop improvement, but most transformation methods rely on tissue culture systems which are mutagenic. The resultant transgenic plants frequently contain undesirable genetic changes (somaclonal variation), in addition to the introduced transgene. Such plants may have reduced agronomic performance, which complicates their use as parents in a breeding program. The development of tissue culture systems that are less mutagenic should enable the production of transgenic plants with superior performance. In this study, agronomic traits were measured for plants regenerated from cultures of two barley (Hordeum vulgare L.) genotypes, using three different tissue culture systems, and compared with the performance of uncultured controls. Plants derived from all three systems were shown to have reduced performance for one or more agronomic traits, but there were clear differences attributable to the culture system. Plants derived from standard embryogenic callus tissues were shown to have the greatest reductions in agronomic performance. Two other tissue culture systems, which had been developed for increased regenerability, showed better performance. Plants derived from highly differentiated, meristematic tissues showed the least reductions in agronomic performance. Plants derived from a modification of the embryogenic callus system—which is characterized by an intermediate level of differentiation—showed intermediate levels of agronomic performance. These results demonstrate that modifications of methodology, in addition to improving plant regenerability, can reduce the level of somaclonal variation in regenerated plants.

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Copyright © 2002. Crop Science Society of AmericaPublished in Crop Sci.42:1303–1308.