Genetic analysis of presence and absence of lint and fuzz in cotton

Abstract

Abstract Cotton fibre mutants that were fuzzless and/or lintless were crossed with each other and a normal genotype (fuzzy, linted) to produce F 2 and BC 1 generations. F 2 segregation ratios from the cross of fuzzless‐lintless × fuzzy‐linted, for fuzzy‐linted, fuzzless‐linted and fuzzless‐lintless were 45 : 15 : 4. From the cross of fuzzless‐lintless × fuzzy‐linted, the F 2 segregation ratios were 9 : 39 : 16 whereas the BC 1 F 1 segregation ratios from the F 1 backcrossed to fuzzless‐lintless were 1 : 3 : 4. These data suggest that the presence or absence of lint and fuzz are controlled by the interaction of four gene loci on non‐homologous chromosomes. We designate these loci as N 1 , N 2 , Li 3 and Li 4 , where N 1 N 1 confers the presence of fuzzy, N 2 N 2 confers inhibition of fuzzy initiation and development, and duplicate gene pairs, Li 3 Li 3 and Li 4 Li 4 , determine the presence of lint. Homozygosity for li 3 li 3 and li 4 li 4 might also inhibit fuzz from development. In other words, they were recessive epistatic to fuzz genes.