A Genetic Study of Number of Involucral Bract Teeth in Cotton
1985
Wilson, F Douglas
Texas 207 is a photoperiodic accession of cotton, Gossypium hirsutum L., that has many toothed involucral bracteoles (bracts) that enclose the flower bud more completely than do the few-toothed bracts of modern cultivars. This character could possibly be of value in deterring small insects, such as thrips, Frankliniella spp., from damaging very small flower buds. The inheritance of number of bract teeth was studied in a series of crosses with Texas 207 as one founder parent (✕ = 17.3 teeth/ bract) and a cultivar, Stoneville 7A (St 7A) as the other (g 8.7). From a cross of a day neutral selection of (T-207 ✕ St 7A) with St 7A, quantitative and qualitative genetic analyses taken together suggested that those two parents differed by at least three pairs of genes which acted additively in concert. Narrowsense heritability, estimated in F₂ on a plant basis, was 46%. I failed to transfer a high number of bract teeth into the 7A background apparently because certain advanced-generation populations from backcrosses to St 7A were too small to recover the many bract-teeth phenotype. However, the genetic analyses suggest that it should be possible to recover that phenotype by growing larger populations of BCₙF₂.
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