Inheritance of a second virescent mutant in American Pima cotton

Eighteen virescent mutants have been described in allotetraploid cotton (Gossypium sp.); however, only one originated in G. barbadense L. These mutants are useful as seedling and mature plant markers for studies of genetic systems and photosynthesis. A second virescent mutant was found in a G. barbadense (Pima) breeding nursery at Maricopa, AZ in 1984. Experiments indicated that it was under genetic control and was a new phenotype in Pima cotton. The objectives of the present study were to determine the inheritance of this new virescent trait and its linkage and allelic relationships with other Gossypium mutants. The genetic studies showed that the virescent trait is inherited as a monogenic recessive, and that it is not linked with 22 Gossypium mutant genes or allelic with v7 in G. barbadense of v1 and v2 in G. hirsutum L. The name virescent-21 and the gene symbol v21 are assigned to the new Pima plant color trait.