The inheritance model for the fiberless trait in upland cotton (Gossypium hirsutum L.) line SL1-7-1:: variation on a theme

Segregating populations were developed to evaluate the inheritance of the fiberless seed phenotype of upland cotton (Gossypium hirsutum L.) line SL1-7-1. We report the inheritance of fuzzy, fuzzless and fiberless seed from crosses of SL1-7-1 with wildtype DP5690, Mexican fuzzless seed UA 3-3 (accession 143), Ballard fuzzless seed (accession 243), and MD17. Results from the F(1), F(2) and F(2:3) progeny derived from the SL1-7-1 X DP5690 indicated that the expression of the fiberless phenotype fit a three loci model with one locus being the dominant fuzzless seed allele N(1) . The other two loci were tested to verify whether they were allelic to either recessive fuzzless seed alleles n(2) or n (3) . Using the segregation ratios of the F(2) progeny derived from the 143 X SL1-7-1 cross and F(2)-derived F(3) families from SL1-7-1 X DP5690 with fuzzy seed (lacked N(1) ), it is proposed that SL1-7-1 lacks the recessive n (2) allele, but contains the n(3) allele in the genotype of SL1-7-1. The third locus was previously not characterized and has been designated as fl(1) (fiberless), therefore, the genotype for the fiberless phenotype of SL1-7-1 is N(1)N(1)fl(1)fl(1)n(3)n(3) . Fiberless lines MD17 X SL1-7-1 were crossed to verify similarities in genotypes between line and the genotype model predictability. Various combinations of the homozygous and heterozygous expression of N(1),n (2),n (3) and fl(1) allele produced plants with lower lint percentages.