Jim Paice MP, Minister of State for Agriculture and Food has declined to apologise after he appeared to suggest that some rapeseeds were better than others.
It followed a BBC interview about agricultural proposals in which he referred to "better rapeseed".
He later returned to TV studios to stress that "all rapeseed is good" and that he had used the "wrong choice of words".
Members of the opposition have said he should quit for effectively suggesting there were "better categories of rapeseed".
The row began on Tuesday morning with remarks Mr Paice gave in an interview with BBC Radio 4 about proposals under consultation to classify oil seed rape better than other Brassicas, including mustard seed.
Mr Paice has not apologised for his remarks in general, but he has written to a rapeseed consumer, saying: "I have always believed that all rapeseed is of equal status, and must be treated as such. I am sorry if my comments gave you any other impression or upset you."
A DEFRA spokesman said, “In the minister’s defence there is often confusion between “rapeseed” and other oilseed crops in the Brassicaceae family. Most are fit for human consumption but others are only fit for giving to birds, er…I mean of the feathered variety.”