Inheritance and Expression of Transgenes in Barley
- Phil Bregitzer *ab and
- Dennis Tonksab
Empirical assessments of transgene inheritance and phenotypic expression will assist in the development of efficient breeding strategies for transgenic germplasm, and guide research into the improvement of transformation techniques. The inheritance of a barley yellow dwarf virus (BYDV) coat protein gene and bar, and the expression of bar as measured by resistance to glufosinate-ammonium damage, was studied in the T1 and T3 generations of barley (Hordeum vulgare L.) populations derived from seven independent transformation events. Most populations deviated from Mendelian inheritance patterns, and several showed evidence of transgene silencing. To further study transgene behavior, several transgenic lines were crossed to a diverse set of nontransgenic cultivars and breeding lines to produce single cross- and backcross-derived populations. In these populations, the inheritance of glufosinate-ammonium resistance generally fit Mendelian expectations for single, dominant loci. Quantitative measurements of glufosinate-ammonium resistance showed heritable variability for glufosinate-ammonium resistance both among and within individual transformation events, but no variability could be attributed to the different genetic backgrounds of the nontransgenic parents. It is concluded that, although transgenic parents such as these can be used in a breeding program, transformation systems that result in greater stability of transgene behavior are desirable.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
Copyright © 2003.