To me, the "... last year the team made a breakthrough by doubling the yield to more than 4.5 tonnes per hectare." part sounds like they changed tack from what

To me, the "... last year the team made a breakthrough by doubling the yield to more than 4.5 tonnes per hectare." part sounds like they changed tack from what they had been trying for the previous 4 decades. Could be a coincidence though.