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Segregating populations were developed to evaluate the inheritance of the fuzzless seed phenotypes in upland cotton (Gossypium hirsutum L.). Accession 143 of the Mississippi Obsolete Variety Collection (MOVC) has a fuzzless seed phenotype. This line carries the n 2 locus which is recessive to the seed fuzz phenotype. Data from the F 2 , BC 1 F 1 , F 2 : 3 , and BC 1 F 2 populations of DP 5690 x 143 fit a two-loci model for expression of the recessive fuzzless seed phenotype. Fuzzless seeds were obtained in n 2 n 2 plants when a second recessive locus (n3) was present. The dominant N 3 allele found in DP 5690 confers the fuzzy seed phenotype in homozygous n 2 plants. Accession 243 of the MOVC carries the N 1 locus, which is dominant to the presence of seed coat fuzz. No variation from expected ratios was observed in the F 2 , BC 1 F 1 , F 2 : 3 , and BC 1 F 2 populations of the DP 5690 x 243 cross. The N 3 allele had no apparent effect on the expression of the N 1 locus. In a cross between accessions 243 x 143, a few plants were observed which were completely devoid of lint and fuzz fiber (fiberless). A fiberless line was developed from one of these fiberless plants. This line was designated MD 17 fiberless. In a cross between DP 5690 x MD 17 fiberless, we demonstrated that at least three loci were involved in the expression of the fiberless phenotype. The involvement of n 2 and n 3 in the expression of this fiberless phenotype was demonstrated in the F 2 progeny of the cross between 143 x MD 17 fiberless. This is the first demonstration that N 1 , n 2 , and n 3 interacted to produce fiberless seed.

Experiments were undertaken to determine whether close linkage between the pilose allele and a locus influencing cotton (Gossypium hirsutum L.) fiber fineness had been misinterpreted as pleiotropy. Pilose (T 1 ), the dominant allele to the t 1 locus, is phenotypically described by a high density of trichomes on the leaf surface, the presence of trichomes on the carpel wall, and increased micronaire. Two lines, 239-17/6 and 250-14/2, were derived from single plant selections of pilose plants in an Empire genetic background (.)

Little is understood about the biochemical basis of differences in quantitative traits of cotton (Gossypium hirsutum L.) fiber. Malate dehydrogenase (MDH) is implicated as an enzyme that may have and effect on extension growth during the development of cotton fiber. Our objectives were, first, to determine if variability among cultivars exists for MDH, and, second, to determine if variability in MDH can be correlated with quantitative traits of fiber. Twenty-four cultivars G. hirsutum were chosen (...)