ARS | Publication request: Molecular markers associated with the immature fiber (im) gene affecting the degree of fiber cell wall thickening in cotton (Gossypium hirsutum L.)

Submitted to: Theoretical and Applied Genetics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: July 27, 2012
Publication Date: January 3, 2013
Citation: Kim, H.J., Moon, H.S., Delhom, C.D., Zeng, L., Fang, D.D. 2013. Molecular markers associated with the immature fiber (im) gene affecting the degree of fiber cell wall thickening in cotton (Gossypium hirsutum L.). Theoretical and Applied Genetics. 126, 23-31.

Interpretive Summary: Cotton fiber fineness and maturity are important properties to determine the fiber quality. These properties are directly affecting the yarn quality. The fineness and maturity are measured indirectly as micronaire (MIC). To understand the genetic control and molecular mechanisms of fiber fineness and maturity, we studied two cotton lines, TM-1 and im mutant, that are almost identical except the latter producing immature fibers. These two lines differ significantly in MIC values. The fibers from im mutant plants were finer and less mature with lower MIC than those from TM-1 plants. A comprehensive fiber property analyses of TM-1 and im mutant showed that the lower MIC of im mutant fibers was due to the lower degree of fiber cell wall thickening as compared to the TM-1 fibers. Using an F2 population comprising 366 progeny derived from a cross between TM-1 and im mutant, we confirmed that the immature fiber phenotype present in a mutant plant was controlled by one single recessive gene im. Furthermore, we identified thirteen DNA markers that were closely linked to the im gene located on chromosome 3. Molecular markers associated with the im gene will lay the foundation to further investigate genetic information required for improving cotton fiber fineness and maturity.

Technical Abstract: Cotton fiber fineness and maturity measured indirectly as micronaire (MIC) are important properties of determining fiber grades in the textile market. To understand the genetic control and molecular mechanisms of fiber fineness and maturity, we studied two near isogenic lines (NILs), Gossypium hirsutum, Texas Marker-1 wild type (TM-1) and immature fiber (im) mutant showing a significant difference in MIC values. The fibers from im mutant plants were finer and less mature with lower MIC values than those from the recurrent parent, TM-1. A comprehensive fiber property analysis of TM-1 and im mutant showed that the lower MIC of fibers in im mutant was due to the lower degree of fiber cell wall thickening as compared to the TM-1 fibers. Using an F2 population comprising 366 progeny derived from a cross between TM-1 and im mutant, we confirmed that the immature fiber phenotype present in a mutant plant was controlled by one single recessive gene im. Furthermore, we identified thirteen simple sequence repeat markers that were closely linked to the im gene located on chromosome 3. Molecular markers associated with the im gene will lay the foundation to further investigate genetic information required for improving cotton fiber fineness and maturity.