ABSTRACT
Various fiber mutants of cotton have been reported since 1920. Two of the best characterized mutants are the naked seed loci, N1N1 and n2n2. Recently, a naked-tufted mutant called 9023 nt4 was developed from the cultivar SC 9023 through chemical mutagenesis. The mutant was tested to determine if it was allelic to either N1, or n2 or was a unique mutant in a new uncharacterized locus. In 1999, one M3 plant from SC 9023 with tufted partially naked seed coat (fuzzless) was identified. In 2004, 2006, and 2007 (Lubbock, TX), 2007 (College Station, TX), and 2011 (Stoneville, MS), the homozygous naked seed mutant was evaluated with the non-mutated wild type parent (SC 9023) in rep-licated trials for agronomic and fiber traits. Crosses between the mutant and the wild type was made at Stoneville, MS in 2009. The F2 of this cross segregated in a 3 fuzzy: 1 fuzzless ratio indicating that the fuzzless trait in the mutant is controlled by a recessive locus. Allelism tests with N1N1, n2n2 and n3n3, lint percent, and fiber trait data indicated that the new locus in the mutant differs from the previously characterized fuzzless seed alleles in that it does not appear to decrease lint percent. We have putatively designated this gene nt4nt4 .