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

Transgenic F 1 hybrids (trF1) were formed between wild mustard (as female) and transgenic
OSR ( GT). No n-transgenic F 1 hybrids ( ntrF1) were obt ained b y crossing wild m ustard ( as
female) with the non-transgenic parent (Westar).
The seeds of GT were sieved into three categories by seed diameter: larger than 1.6 mm
(L), s maller t han 1.2 mm ( S), a nd m edium-sized be tween 1.2 a nd 1.6 m m ( M). T hese
categories were the same as those used in previous studies on t he hybridization of B. napus
with five wild relatives (Wei & Darmency 2008). The three seed categories of mustard were:
larger than 1.2mm, smaller than 1.0mm and between 1.2-1.0 mm. Because of the seeds of trF1
and ntrF1 were smaller than 1.2 mm, they were separated by 1.0 and 0.9 mm.
Monoculture experiment
The three seed categories of mustard were directly sown in the field on March 19, 2008.
The e xperimental de sign c onsisted i n t hree bl ocks, e ach ha ving t hree pl ots w ith a di fferent
plant density: 400 plants /m 2 (high), 100 plants /m 2 (medium) and 25 plants /m 2 (low), i.e. the
distance be tween s owing pos itions w as a rranged i n t hree l evels: 5 c m, 10 c m a nd 20 c m,
respectively. Each plot had 60 sowing positions in 5 rows and 12 columns. Twenty positions
per plot were taken at random for one seed category and sowed with five seeds each position.
Emerged seedlings were counted, and then randomly thinned to one plant per position.
Multi-culture experiment
In o rder t o s tudy t he i nterspecific competition, t he f our t ypes of pl ants, B. j uncea
(mustard), transgenic B. napus (GT), transgenic F1 (trF1), and non-transgenic F1 (ntrF1), were
co-cultured together. Seeds of the three categories were directly sown in the field on March
31, 2008. T here were three blocks in this experiment and each block contained two plots of
plant density: 100 pl ants /m 2 and 25 pl ants /m 2 , i.e. the distance between plants at these two
densities was 10 cm and 20 cm, respectively. Five seeds of every plant type per seed category
combination w ere s own a t 5 pos itions i n each plot, w ith 60 pos itions i n 10 r ows a nd 12
columns per plot. Emerged seedlings were recorded, and then randomly thinned to one plant
per position as in the monoculture trial above.
Measurements
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