EFFECTS OF MOTES ON LINT QUALITY OF INTERSPECIFIC COTTON HYBRIDS

Lint of interspecific hybrids (ISHs) of cotton (Gossypium hirsutum L. x G. barbadense L.) tends to contain a high proportion of impurities w hich reduce the quality of yarn and fabric. Much of these impurities a re related to the presence of motes (aborted ovules or seeds) in the s eed cotton produced by these hybrids. This study was aimed at determin ing the effect of motes of various sizes and fiber physical properties on the number of neps (tangled fibers) in the lint from ISHs. Lint fr om 13 ISHs and a control cultivar (G.b. cv. Pima S-5), grown in the fi eld under either irrigated or dryland conditions, were examined for th e number of motes, number of neps, and fiber physical properties. The effects of motes of various sizes and lint properties on nep numbers w ere examined by means cif correlation and multivariate regression anal yses. Nep frequency was most closely positively related to the number of medium-size motes (1-3 mm in width and 3-5 mm in length), which was introduced into seven regression equations out of the nine examined c ases. Further, nep frequencies were closely negatively related to the percentage of mature fibers, which was introduced into six of the regr ession equations. R-2 values of the resulting equations were between 0 .51 and 0.79. Selection for a reduced number of medium motes and a hig h percentage of mature fibers appears to be a possible approach for im proving the lint quality of cotton ISHs.