Gene Induced Mutation of a Heritable Cytoplasmic Factor Producing Male Sterility in Maize

Abstract

The recessive gene iojap (ij) in maize induces an irreversible mutation of plastid primordia, resulting in white or green-white striped plants. The same gene also affects a different cytoplasmic factor concerned with development of the male gametophyte. When ij plants are used as egg parents in crosses with normal, male-fertile plants, the F1 progenies may consist of some completely or partially male-sterile plants. Crosses of the male-sterile F1 plants with unrelated male-fertile individuals give only male-sterile offspring. The plastid primordia and the factor determining male sterility mutate independently of each other, indicating that they are due to two different cytoplasmic factors. The factor for male sterility is thought to be particulate owing to the occurrence of partially sterile plants. It is suggested that the particles involved are mitochondria, although some other cytoplasmic component may be involved.