Five cultivars of upland cotton were planted at 10-day intervals from April 20 through -June 1, 1980-1983. 'Camd-E', 'Cascot L7', 'DES 56', 'Deltapine 41', and 'Stoneville 213' were selected as representatives of differing maturity groups. The objective of this study was to assess the progress in developing yield-competitive and early-maturing cultivars. Entries were planted in a split plot design with 4-row plats, 21 m long and 97 cm between rows. The test site was Loring s. 1. and all cultural practices were as recommended for the locale with furrow irrigation.

Camd-E, representative of "determinate" type of earliness, generally matured significantly earlier than DES 56 and Stoneville 213 regardless of planting date. Camd-E also yielded as well as or better than Stoneville 213, representing full-season types, when planted May 20 or June 1, but not when planted earlier than May 20. DES 56, as representative of "indeterminate" type of earliness, often matured significantly earlier than Stoneville 213 when planted late and was competitive in yield with Stoneville 213 regardless of planting date. These data suggest that progress is being made in developing high yielding genotypes with a broadened range of acceptable planting dates in the Mid-South.