A Dominant Round Leaf Mutant in Cotton1

In 1966, R. H. Dilday found a mutant cotton ( Gossypium hirsutum L.) plant showing a combination of the characteristics of the marker mutants round leaf ( rl ), frego bract ( fg ), strap leaf ( s ), Smooth leaf loci ( Sm 1 , Sm 2 , Sm 3 ), and open bud ( ob ). Inheritance and linkage tests showed that the mutation was conditioned by a dominant gene. In the homozygous state the new mutant is functionally lethal, and therefore it must be maintained as a heterozygote. Linkage associations were not found between the new mutant and 17 marker loci tested. However, the glabrous and abnormal bract expressions of the new mutant were epistatic to the expressions of the Pilose ( H 2 ) and fiego bract ( fg ) markers. It is proposed that this new mutant be named Round leaf‐2 and assigned the gene symbols Rl 2 , Rl 2 .