Hi dear,
          First of all, please don't worry about your percentage.Life is all about ups and downs.You have secured such a good percentage in 10th so what if you secured less in 12th.We should be ready to face failures in life too.Sometimes, things don't happen as we want them to happen.So, it is all okay ,life doesn't stop with all these things.
So, to become a agricultural scientist , you need to pursue a bachelor's degree in agricultural science, biology, chemistry or any related field.You may go for master's  or PhD for advanced positions.
Skills required are :

• Laboratory & field research
• Data analysis
• Knowledge of biosecurity measures

The basic eligibility for bsc agriculture is +2  with science subjects with a minimum of 50% marks.
So, if you work hard for your goal and acquire the relevant skills in your field,you will surely be successful.
Best of Luck!!