Stoneville Pedigreed Seed Company is introducing the new variety ST 580 for the 2001 planting season. ST 580 was developed from a cross between ‘ST 468’ and ‘DPL 5415’. The variety was developed through traditional plant breeding methods using a modified pedigree breeding program. ST 580 is similar in maturity to NuCotn 33B, with longer fiber length and higher fiber strength than NuCotn 33B. Yield comparisons in 61 Stoneville intra-company trials from 1997 through 2000 indicate that ST 580 produces significantly more lint yield than NuCotn 33B. Planting seed of ST 580 will be available to growers across the Cotton Belt for the 2001 growing season.