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 which reduce the quality of yarn and fabric. Much of there impurities are related to the presence of motes (aborted ovules or seeds) in the seed cotton produced by these hybrids. This study was aimed at determining the effect of motes of various sizes and fiber physical properties on the number of neps (tangled fibers) in the lint from ISHs. Lint from 13 ISHs and a control cultivar (G.b. cv. Pima S-5), grown in the field under either irrigated or dryland conditions, were examined for the number of motes, number of neps, and fiber physical properties. The effects of motes of various sizes and lint properties on nep numbers were examined by means of correlation and multivariate regression analyses. 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 cases. Further, nep frequencies were closely negatively related to the percentage of mature fibers, which was introduced into six of the regression equations. R² values of the resulting equations were between 0.51 and 0.79. Selection for a reduced number of medium motes and a high percentage of mature fibers appears to be a possible approach for improving the lint quality of cotton ISHs.