A New Ligon-Lintless Mutant (liy) in Upland Cotton

Abstract

Cotton fiber mutants are useful tools for understanding the genetics and physiology of cotton fiber development. Currently, there are two naturally occurring, dominant lintless mutant lines, Ligon-lintless-1 (Li1) and Ligon-lintless-2 (Li2), and one man-made mutant line, Ligon-lintless-x (Lix), that exhibit extremely short lint fibers. Here we report a new lintless mutant that is the result of artificial chemical mutagenesis. In 2008, the cotton line MD 15 (PI 642769) was mutagenized with 3.2% v/v ethyl methane sulfonate (EMS). In 2010, a single Ligon-lintless-type plant was identified among the 2,000 M2 mutant progeny plants and was designated liy. This plant was crossed with the wild-type MD 15 with the objective of determining the genetic control of the lintless trait. Unlike Li1, Li2, and Lix, which are controlled by a single dominant gene, this new lintless trait is controlled by a monogenic recessive gene designated as liy. The liy plant is short and stunted and has an okra-leaf phenotype. The liy gene is not allelic to either Li1 or Li2. The genetic loci controlling these four Ligon-lintless mutations are located on four different chromosomes. This new lintless mutant will be useful in further investigating fiber elongation in cotton.