Characteristics and Fitness Analysis through Interspecific Hybrid Progenies of Transgenic Brassica napus and B. rapa L. ssp.

Abstract

Interspecific hybridization between transgenic crops and their wild relatives is a major concern for transgene dispersal in the environment. Under controlled conditions, artificial hand pollination experiments were performed in order to assess the hybridization potential and the fitness of interspecific hybrids between Brassica rapa and genetically modified (GM) Brassica napus. Initially, six subspecies of B. rapa were hybridized with GM B. napus through hand pollination. In the resulting F1 hybrids, the combination of B. rapa ssp. narinosa (♀) × GM B. napus (♂) had the highest crossability index (16.9 ± 2.6). However, the F1 selfing progenies of B. rapa ssp. rapa (♀) × GM B. napus were found to be more effective in producing viable future generations with the highest crossability index (1.6 ± 0.69) compared to other subspecies. Consequently, they were used for the generation of F2 and F3 progenies. The 18 different morphological characteristics among the parental cross-combinations and F1 hybrid progenies were measured and visualized through hierarchical clustering. Different generations were found to be grouped based on their different morphological characteristics. The chromosome numbers among the interspecific hybrids ranged from 2n = 29 to 2n = 40. Furthermore, the SSR markers revealed the presence of genomic portions in the hybrids in comparison with their parental lines. There is a high possibility of transgene flow between GM B. napus and B. rapa. The study concluded that the interspecific hybrids between B. napus and B. rapa can be viable and can actively hybridize up to F3 generations and more. This suggests that the GM B. napus can disperse the transgene into B. rapa, and that it can pass through for several generations by hand pollination in a greenhouse environment.

No fitness cost in Brassica rapa (wild turnip) populations associated with transgenic glyphosate and non-transgenic AHAS-inhibiting herbicides resistance

“…A recent study showed that the F1 crop wild hybrid between oilseed rape and wild turnip can produce several viable and fertile generations being able to transfer the herbicide-resistant genes to their progenies. However, it was observed that the following generations decreased in tness compared with the F1 hybrid (Sohn et al 2022). Furthermore, other authors maintained that rst-generation hybrids have a reduced fertility, features that must be overcome in subsequent backcross generations for stable introgression to occur (Warwick et al 2008).…”

“…Characterization of the tness cost in a feral population associated with the acquisition of herbicide-resistance genes provides an evolutionary framework needed to assess their impact on the environment and ecology (Sohn et al 2022). A recent study showed that the F1 crop wild hybrid between oilseed rape and wild turnip can produce several viable and fertile generations being able to transfer the herbicide-resistant genes to their progenies.…”

“…Hybridization experiments showed that all F1 hybrids between oilseed rape and turnip were morphologically like oilseed rape but they presented a reduced pollen fertility (around 55%) (Warwick et al 2003). Despite this, there are environments when F1 hybrids are as suitable or better than their parents (Sohn et al 2022).…”

Transcriptome Shock in Developing Embryos of a Brassica napus and Brassica rapa Hybrid

“…napus (AACC, 2n = 4x = 38) is one of the most important oilseed crops, which is widely cultivated in China. B. rapa (AA, 2n = 2x = 20) is frequently used as an important genetic resource for the genetic improvement of B. napus [32][33][34]. In this study, a synthetic hybrid (AAC, 3x = 29) was constructed by hybridization between B. napus (maternal parent) and B. rapa (parental parent).…”