Inheritance of Male‐sterile Mutant Ms12 in American Pima Cotton1

Abstract

A male‐sterile American Pima cotton (Gossypium barbadense L.) plant was found in the field in 1976. Genetic male steriles in cotton are useful as markers and in controlled crossing by providing male‐sterile stocks as female parents. In this study our objectives were to determine the inheritance of the genes conditioning the Pima male‐sterile trait and to detect possible linkage between Pima male‐sterile and other mutant genes in cotton. Crosses made between Pima male‐sterile and normally male‐fertile ‘Pima S‐5’ plants produced male‐sterile and male‐feritle F1 plants in a 1:1 ratio. BC1 progenies from sterile F1 plants crossed with Pima S‐5 fit a ratio of 1 sterile : 1 fertile. Fertile F1 plants crossed with Pima S‐5 produced only fertile progeny. These data show that the male‐sterile trait is conditioned by one dominant gene. We propose the name Male‐sterile‐ 12 and the gene symbol Ms12 for this trait. Linkage tests between Ms12 and 23 Gossypium mutant genes were negative. Relationships between Ms12 and other genetic male steriles in cotton are discussed.