Statistical analysis using rainfall and time trends accounts for county average flue-cured tobacco yields in North Carolina from 1940 to 1987. A change in the annual yield growth path occurred in 1965. The data are consistent with the hypothesis that the switch from acreage allotments to poundage quotas for flue-cured tobacco beginning in 1965 caused a decline in both yield levels and rates of annual yield increase. Both declines are fully consistent with changed relevant incentives facing growers and researchers