It depends on a few factors whether you will be eligible for agriculture colleges with a score around 250 in CUET and not selecting ICAR.

Some universities might accept your CUET score for admission to B.Sc. Agriculture programs even if you didn't choose ICAR during the application. However, it's best to check with the specific universities you're interested in. Their websites or admission brochures should clarify their eligibility criteria.

Even if universities accept your CUET score, a score of 250 might be on the lower end. The cut-off marks for B.Sc. Agriculture programs vary depending on the university, course popularity, and the total number of applicants.A score of 250 might be sufficient for some private agriculture colleges, but for government colleges, it's likely on the lower end.

https://university.careers360.com/articles/icar-aieea-exam-pattern

I hope it helps!