Genetic improvement of naked-tufted seed mutants in upland cotton (Gossypium hirsutum L.)

This research evaluated the potential for using sexual crosses for genetic improvement of fiber yield, lint percent, AFIS fiber quality, and fiber initiation of two naked-tufted mutants of cotton (Gossypium hirsutum L.). The naked tufted lines were crossed with ten fuzzy breeding lines to generate 10 F-2 populations. The F-2 distributions were tested with Chi Square for Goodness of Fit to two monogenic and two digenetic segregation ratios. Five of the six F-2 populations made with Atlas-NS-129 segregated as either a single dominant gene (3 Naked-tufted: 1 fuzzy) or as two dominant genes (9 Naked-tufted: 7 fuzzy). Three of the four F-2 populations made with SC 9023-ns-57 segregated as either a single recessive gene (3 Fuzzy: 1 naked-tufted) or as duplicate recessive genes (9 Fuzzy: 7 naked-tufted). However, the F-2 populations when crossed with the Fuzzy line of Tejas 48 showed a reversal of dominance. The F2 population of Atlas-NS-129 X Tejas 48 fit a 9 Fuzzy: 7 naked tufted ratio expected of two recessive genes. The F-2 population of the cross of SC 9023-ns X Tejas 48 fit a 3 Naked-tufted: 1 fuzzy ratio expected of a single dominant gene. Additional studies will be necessary to fully determine the number of gene(s) and the expected phenotypic ratios of individual naked-tufted mutants in crosses with fuzzy seeded breeding lines. Eight of the F-2 and F-3 populations were also evaluated for lint yield, lint percent and AFIS fiber quality traits. The F-2 and F-3 populations of the cross of Atlas-NS-129 X Holland 338 produced the highest average lint yields (1089kgha(-1)) as well as excellent fiber quality. These data indicate that it may be possible to develop relatively high yielding naked tufted cultivars by crossing these mutant lines with elite higher yielding breeding lines.