Hybridization between transgenic Brassica napus L. and its wild relatives: Brassica rapa L., Raphanus raphanistrum L., Sinapis arvensis L., and Erucastrum gallicum (Willd.) O.E. Schulz

• Published in: Theoretical and applied genetics 2003-08, Vol.107 (3), p.528-539
• Main Authors: WARWICK, S. I, SIMARD, M.-J, LEGERE, A, BECKIE, H. J, BRAUN, L, ZHU, B, MASON, P, SEGUIN-SWARTZ, G, STEWART, C. N
• Format: Article
• Language: English
• Subjects: Biological and medical sciences; Brassicaceae - genetics; Brassicaceae - physiology; Cell physiology; Cell transformation and carcinogenesis. Action of oncogenes and antioncogenes; Drug Resistance - genetics; Experiments; Fundamental and applied biological sciences. Psychology; Genetics; Genetics, Population; Green Fluorescent Proteins; Hybridization; Hybridization, Genetic; Luminescent Proteins; Molecular and cellular biology; Phenotype; Plants, Genetically Modified - genetics; Ploidies; Pollen - physiology; Polymorphism, Restriction Fragment Length; Quebec; Seeds
• ISSN: 0040-5752; 1432-2242
• DOI: 10.1007/s00122-003-1278-0

The frequency of gene flow from Brassica napus L. (canola) to four wild relatives, Brassica rapa L., Raphanus raphanistrum L., Sinapis arvensis L. and Erucastrum gallicum (Willd.) O.E. Schulz, was assessed in greenhouse and/or field experiments, and actual rates measured in commercial fields in Canada. Various marker systems were used to detect hybrid individuals: herbicide resistance traits (HR), green fluorescent protein marker (GFP), species-specific amplified fragment length polymorphisms (AFLPs) and ploidy level. Hybridization between B. rapa and B. napus occurred in two field experiments (frequency approximately 7%) and in wild populations in commercial fields (approximately 13.6%). The higher frequency in commercial fields was most likely due to greater distance between B. rapa plants. All F₁ hybrids were morphologically similar to B. rapa, had B. napus- and B. rapa-specific AFLP markers and were triploid (AAC, 2n = 29 chromosomes). They had reduced pollen viability (about 55%) and segregated for both self-incompatible and self-compatible individuals (the latter being a B. napus trait). In contrast, gene flow between R. raphanistrum and B. napus was very rare. A single R. raphanistrum × B. napus F₁ hybrid was detected in 32,821 seedlings from the HR B. napus field experiment. The hybrid was morphologically similar to R. raphanistrum except for the presence of valves, a B. napus trait, in the distorted seed pods. It had a genomic structure consistent with the fusion of an unreduced gamete of R. raphanistrum and a reduced gamete of B. napus (RrRrAC, 2n = 37), both B. napus- and R. raphanistrum-specific AFLP markers, and had