Yup agrees with Carla. Also you don't need to always have someone at the berry bush. If there's enough food in your bin (like 150 or so ... even 100 is good for early on in the game), allow that farmer to do some research. Then once your food dips below a certain point, put that farmer back on the berry bush.

This way you get research points AND you give the berry bush a rest. Good luck!