Genetic Trait Effects on Nonlint Trash of Cotton

Genetic traits that reduce seed‐cotton (Gossypium hirsutum L.) trash or improve cleanability should improve lint grade and preserve fiber quality. Onr objective was to evaluate morphological traits that reduce trash and improve cleanability and grade. Twelve near‐isolines involving four leaf shapes (normal, semi‐okra, okra, and superokra) in two genetic backgrounds (LA 213‐613 and MD 65‐11), bract types (normal and frego), and two leaf‐pubescence levels (hairy and semi smooth) were grown for 2 yr at three locations in Louisiana. Seed‐cottun was harvested with a spindle‐picker and ginned on a miniature version of a commercial gin. Amount and type of trash was determined before and after (feeder apron) seed‐cotton cleaning, and after zero, one, and two saw‐type lint cleaners. Semi smooth and super‐okra leaf traits reduced motes by 25 and 15% and small‐leaf trash at the feeder apron by 47 and 20%, respectively, compared with the check. They produced grades similar to the check with one less lint dcaner. Frego‐bract isolines had less leaf and bract trash in lint than the normal‐bract check at any level of lint cleaning. Use of genetic traits such as semi smooth and super‐okra, and to a lesser extent sub‐okra and frego bract, can be used to reduce lint trash and improve cotton grade. Reductions in motes could help reduce the seed‐coat fragment‐white spot (dead fiber) problem in fabric dying.