UNIVERSITE DE BOURGOGNE THÈSE Yongbo LIU - Université de ...

then t ransfer t ransgenes t o f urther g enerations i n t he r ealistic ag ro-ecosystem w here u n-
cropped and cropped areas coexist.
In this study, we aim to investigate the behavior of the progenies of spontaneous hybrids
between w ild B. j uncea and a he rbicide-resistant g ermplasm o f B. nap us similar to th ose
commercialized cultivars under the Clearfield® technology. We studied the formation of F2
and BC1 progenies, whether they may grow and reproduce under field conditions, and whether
their p erformances ar e ch anged acco rding t o t he p resence o f t he he rbicide-resistance g ene.
Instead of exploring the possibility of transgene introgression into the wild species, which has
been a lready explored [17], t his w ork f ocused on t he l ikelihood of t he e mergence of
backcrossed plants that could behave like B. napus volunteer-like plants.
Materials and methods
Hybrids
A w ild a ccession of Brassica j uncea (2n=36, AABB) from T urkey w as obt ained f rom t he
INRA laboratory collection of weeds (ref. X04-021) in Dijon, France. A mutant B. napus cv.
Brutor, ( 2n=38, A ACC), b earing a s ingle-gene dom inant r esistance t o c hlorsulfuron, a
sulfonylurea he rbicide i nhibiting t he A cetoLactate S ynthase (ALS), w as pr ovided b y M .
Renard [ 18]. T hese t wo s pecies were grown i n mixture i n i nsect-proof c ages c ontinuously
provided w ith houseflies, Musca dom estica, i n order t o f acilitate r andom pol lination. T he
seeds o f B. j uncea were s own i n a g reenhouse at 22°C unde r na tural l ight, a nd t hen t wo-
leaved seedlings were sprayed with 2.5 g a.i. ha -1 chlorsulfuron in 300 L of water (Glean, Du
Pont de Nemours, France). Eleven out of 8,238 seedlings survived (0.13 %), and these plants
were confirmed t o be i nterspecific h ybrids s ince t hey s howed m olecular m arkers of bot h
parents (not shown).
Progeny of hybrids
Branches of all the hybrid plants were cut and planted in the soil to multiply the hybrids.
The hybrid cuttings were grown in the greenhouse and entirely covered by a pollen-proof net.
Anthers of f lowers o f 2 4 c uttings f rom a ll e leven h ybrids were r emoved a nd t he s tigmas
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