To select agronomically useful transgenic plants, a large number of transgenic events are initially produced, gene transfer
confirmed, and advanced to obtain homozygous lines for testing in field trials. Direct
in planta assays for identifying the transgene carriers in the segregating progeny are based on the activity of selectable marker gene
and are easy, simple and inexpensive. For this purpose, expression of
bar gene as measured by tolerance to damage by glufosinate ammonium, the active ingredient in the herbicide BASTA, was investigated.
Dose damage curves were generated by leaf paint tests with BASTA on four genotypes of sorghum. Transgenic plants were characterized
in terms of sensitivity to the concentration of glufosinate ammonium. In transgenics, symptoms of BASTA swab tests at different
growth stages and PCR analysis for
cry1B were carried out and correlated. Germination tests could not be employed for large scale evaluation of transgenic progeny
because of mortality of tolerant seedlings after transplantation to soil. Based on the above findings, a simple, inexpensive,
time-saving, two-step scheme for effective evaluation of transgenics and their progeny containing
bar gene as selection marker using BASTA swab tests is described.
Keywords
Bar
- Correlation - Leaf paint - Transgenic breeding