Basic changes in varieties planted resulted in positive effects on soybean production in the Mississippi Delta. Traditionally group VI and VII varieties were planted; they could not be planted before May 10, because too early flowering might occur in response to their photoperiodicity. Planting was after May 10 and harvest was in October and November. A shift to Group IV varieties, photoperiod neutral and short cycle, permitted earlier planting and harvest in August. Cotton would benefit greatly from the same shifts.