A New Fuzzless Seed Locus in an Upland Cotton (<i>Gossypium hirsutum</i> L.) Mutant

Abstract

Various fiber mutants of cotton have been reported since 1920. Two of the best characterized mutants are the naked seed loci, N 1 N 1 and n 2 n 2 . Recently, a naked-tufted mutant called 9023 n t 4 was developed from the cultivar SC 9023 through chemical mutagenesis. The mutant was tested to determine if it was allelic to either N 1 , or n 2 or was a unique mutant in a new uncharacterized locus. In 1999, one M 3 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 F 2 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 N 1 N 1 , n 2 n 2 and n 3 n 3 , 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 n t 4 n t 4 .