In recent years the entire cotton industry in North Texas Blacklands has been threatened by adverse environmental factors. Heavy late-season insect infestations and high rainfall in the fall harvest period have made a serious negative impact upon cotton production. There has been a shift by many growers toward planting full-season cultivars with their promise of higher yields and quality premiums. The later maturing varieties have exacerbated some of the environmental problems.

There is a need to develop an easy and effective method of measuring earliness of crop maturity. In this project five commercial cultivars were grown for comparison. Daily white bloom counts, weekly open boll counts, and weekly harvests were performed. There was a strong relationship between white blooms, open bolls and lint yield. The most practical measures of earliness of a cotton crop are most likely those found to be associated with the percent open bolls at a given time or the percent of total lint produced by the fourth week after the appearance of the first open boll.