ABSTRACT
Caducous bract cotton with 52 chromosomes was developed after many years of hybridization and selection. The transfer of caducous bract from the wild lintless diploid species G. armourianum to commercial cultivars was started by crossing G. hirsutum (2n=4X=52) with G. armourianum (2n=2X=26) and doubling the chromosome number of the sterile hybrid with colchicine to produce a 78 chromosome hexaploid (2n=6x=78) cotton. Once the caducous bract trait was identified in the hexaploid, a back-cross program using commercial cultivars as the recurrent parent was started to bring the chromosome number back to 52. After two cycles of back-cross breeding and selections, 52 chromosome caducous bract cottons were isolated. Penetrance and expressivity of the caducous bract trait is variable in the progenies. Preliminary genetic analysis indicate the caducous bract is inherited as a recessive trait.
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