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Growth and reproduction in the field
The experiment with BC1J and F2 suffered a strong insect attack previous to the setup of the
net; therefore, this trial had to be abandoned. In the experiment with BC1N and oilseed rape,
the s eedling m ortality and a bsence of f lowering i n t he f ield w ere m ore frequent f or t he F 2
generation ( 10 out of 38) t han f or BC1N ( 10 out of 72) a nd B. napus (9 out of 53) . BC1N
plants w eighted m ore t han t hose of B. napus , a nd F 2 had i ntermediate weight ( Table 2.7).
Both BC 1N and F 2 plants showed lower seed weight, per-seed weight and seed germination
percentage t han B. napus . T he F 2 produced l ess s eeds t han B. napu s, a nd B C1N ha d
intermediate production (Table 2.7).
Table 2.6. Percentage of resistant plants in the progeny of susceptible B. napus, BC1N and F2
plants in the field experiment.
Plant type Number of plants Progeny Percentage of
Total With R progeny Resistant Susceptible resistant
BC1NS 35 13 a 48 13925 0.34
F2S 4 4 81 2254 3.6
B. napus 47 2 3 43574 0.007
a identified as BC1NS* in Fig. 2.6 and 2.7.
There w ere s ignificant c orrelations be tween s eed num ber a nd t otal a boveground bi omass
(plant weight plus seed weight) for the three plant types (P< 0.001, Fig. 2.5). The ranking of
the slopes of the linear regression equations of seed number in terms of biomass, from the
higher to the smaller value, was: B. napus, all phenotypes of BC1N as intermediate, and then
F2. S eed number and bi omass of F2 showed greater v ariability than t hose o f B C1N, wh ich
were also more variable than those of B. napus, as indicated by the ranking of the coefficients
of determination (R 2 ).
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