Submitted to: Journal of Cotton Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 29, 2010
Publication Date: May 3, 2010
Citation: Zeng, L., Meredith Jr, W.R. 2010. Neppiness in an Introgressed Population of Cotton: Genotypic Variation and Genotypic Correlation. Journal of Cotton Science. 14:17-25. Interpretive Summary: Neps and seed coat fragments are impurities in ginned cotton fibers and can severely affect yarn quality if they remain in raw fibers after cleaning. Neps are small fiber entanglements that occur during cultivation, harvesting, and ginning. Seed coat fragments in ginned fibers are particles from damaged seed coats during harvesting and ginning. The removal of these particles will be difficult because most of them are attached to fibers. The impurities from neps and seed coat fragments will remain un-dyed at dyeing stage in textile processing and cause ‘white specks’ in fabrics. Development of cotton cultivars with low nep content and seed coat fragments while maintaining high lint yield and high fiber quality will be essential in cotton breeding. An exotic germplasm source derived from wide crosses was evaluated for nep content and seed coat fragments in ginned fibers and their relationships with lint yield and other fiber properties. Tremendous genetic diversity for nep content and seed coat fragments was identified in this germplasm source. Twelve lines were selected with low nep content and seed coat fragments and excellent fiber quality in other properties. These lines can be used as parents in crossing to improve these traits in cotton cultivars.
Technical Abstract: Neps and seed coat fragments are two types of impurities in ginned fibers causing severe problems in textile processing during spinning and dyeing. The study was designed to investigate the genotypic variation for neps and seed coat fragments remaining in ginned fibers in an introgressed population and analyze interrelationships between the neppiness and other fiber properties. Two hundred lines of a population, i.e., JohnCotton (JC) germplasm, derived from multiple crosses between Gossypium hirsutum L. and G. barbadense L. and five cultivars were planted at two locations in 2006 and one location in 2007 with two replicates each. The neps and seed coat fragments were measured using Advanced Fiber Information System. Genotypic variations of nep count and seed coat nep (SCN) count in the JC germplasm were highly significant (p<0.001). Wide ranges of nep count (70 to 288 counts g-1) and SCN count (2.7 to 16 counts g-1) were identified among the 200 lines. The mean of the SCN in JC population was not significantly (p<0.05) different from the mean of the cultivars. Lint yield was negatively (favorably) correlated with nep count (r=-0.47) and SCN (r=-0.31). Unfavorable correlations were identified for nep count vs. fineness (r=-0.75) and SCN count vs. fiber bundle strength (r=0.60). Nep count was unfavorably correlated to 2.5% span length (r=0.56), but not correlated to 50% span length (r=0.10). Two lines were selected with nep count less than 90 cnt g-1 and fineness lower than 180 mg km-1 and ten lines were selected with SCN less than 6 g-1 and strength greater than 230 kN m kg-1.