INTERSPECIFIC GENE FLOW AS A COMPONENT OF RISK ASSESSMENT FOR TRANSGENIC BRASSICAS

Interspecific hybrids were produced between three diploid weeds (R. raphanistrum, RrRr, 2n=18, B. adpressa, AdAd, 2n=14 and S. arvensis, SarSar, 2n=18) and B. napus (AACC, 2n=38) either a transgenic herbicide resistant rapeseed, under controlled conditions (i.e. hand pollination and embryo rescue) or a male sterile rapeseed under field conditions.
Per 100 pollinated flowers, for the first method, 0.0 (with S. arvensis as female parent) to 11.6 (with B. adpressa as male parent) embryos were obtained whereas the number of seeds ranged from 0.18 (with S. arvensis) to 23.8 (with R. raphanistrum) under open pollination.
Most of the hybrids had the expected triploid structure (ACX) except some amphidiploids plants (AACCXX). The meiotic behaviour of the triploid hybrids revealed that recombination might occur preferentially between AC and Rr genomes.
Seed set of Fl interspecific hybrids was in any case low under optimal conditions.
In the advanced progenies of B. napus-R. raphanistrum hybrids, the chromosome number remained high as well as the percentage of rapeseed specific molecular markers; same observations were realized on B. napus-B. oleracea progenies.
From these results, the possibility of gene flow between crucifer species is discussed.

ISHS Brassica Symposium – IX Crucifer Genetics Workshop

A.M. Chèvre, F. Eber, A. Baranger, M.C. Kerlan, P. Barret, G. Festoc, P. Vallée, M. Renard

https://doi.org/10.17660/ActaHortic.1996.407.21