This compares ability to transfer traits from wild to domesticated with ability to transfer from domesticated to wild. But the argument doesn’t concern transferring from wild to domesticated.

This suggests we can speed up the rate of transferring flower color by including a greater proportion of domesticated plants. But this doesn’t relate to whether a different trait — pesticide resistance — can be transferred.

This undermines the argument by suggesting the radishes used in the experiment might not support a conclusion about trait transfer in other kinds of plants.

If anything, this undermines the argument by pointing out a difference between the trait of flower color and the trait of pesticide resistance. This suggests the transferrability of flower color might not apply to pesticide resistance.

If the transfer of flower color observed in the experiment is more difficult than almost any other kind of transfer of trait between any related plant species, that suggests transfer of pesticide resistance is likely to be easier, which supports the claim that it will occur.