The im Mutant Gene Negatively Affects Many Aspects of Fiber Quality traits and Lint Percentage in Cotton

Abstract

Immature fiber (im) is a cotton (Gossypium hirsutum L.) fiber recessive mutant on chromosome 3 that causes abnormal fiber characteristics, fineness, and a low fiber weight. Here, the im mutant and five cotton lines, two from G. hirsutum accession TM‐1 and I4005 and three from different chromosome segment introgression lines (CSILs) from chromosome 3 of Gossypium barbadense L. ‘Hai7124’ in the background of G. hirsutum accession TM‐1, were compared for differences in fiber characteristics, fiber quality traits, and lint percentage. Combined F2 and F2:3 mapping populations were produced by crossing im with the five lines, which further confirmed the negative effect of im on fiber quality traits and lint percentage. Except for short fiber index, other fiber traits showed a significant correlation with each other in the five mapping populations. Three traits in particular, micronaire, maturity, and lint percentage, showed a correlation coefficient of >0.8 (P < 0.001). The im mapping and quantitative trait locus (QTL) analyses revealed QTLs responsible for various measured characteristics in each population. The integration of QTLs from the different populations showed that most QTLs related to multitraits from different populations were clustered near the im locus with a high percentage of phenotypic variance. The im mutant significantly affected the phenotypic value of these traits, which indicated that im played an important role in fiber development, and it had a great impact on fiber quality traits and lint percentage.