Inheritance of a Second Wrinkled Leaf Mutant in American Pima Cotton.

Leaf morphology mutants arise from time to time in cotton (Gossypium spp.). These mutants are useful as markers for the study of genetic systems and for developmental studies of leaf morphology. One such mutant with wrinkled leaves appeared as a single plant in a 1982 breeding row (82-748) of American Pima cotton (G. barbadense L.) at Phoenix, AZ. The objectives of the present study were to determine the inheritance of the wrinkled leaf trait and its allelic and linkage relationships with other Gossypium mutants. The wrinkled leaf phenotype is inherited as a monogenic recessive. It expresses on successive leaves beginning with the first sympodial branch produced from Nodes 6 through 8 on field grown plants. The wrinkled leaf trait was not allelic with three other leaf mutant genes nor was it linked with 22 Gossypium mutant genes. The name wrinkled leaf-2 and the gene symbol wr2 are proposed for the new leaf trait. The new trait should be useful in genetic and developmental studies as an easily scored recessive phenotype affecting leaf morphology.