Hey Nandula
Yes you can take B.Sc. Agriculture.
Entry to this field starts from undergraduate level. After completion of 10+2 in Science stream (class 12th) with chemistry, physics, and maths/ biology/ agriculture as the subjects one can opt for Bachelors degree in Horticulture as a separate discipline or as a subject of BSc Agriculture Science.
The candidates those desire to take admission in UG in Horticulture has to appear in HORTI CET  Entrance Test. The candidates will get the admission through a counselling a process just after the result announced.
Hope this information helps.