Genic male-sterile maize

A method of producing hybrid maize using a genic male-sterile parent comprising the steps of:

• breeding a first maize line homozygous at a selected male-sterile locus and carrying a suppression factor in its genome;
• breeding a second maize line homozygous for an insertion mutated male-fertile allele allelic with the male-sterile locus and mutated by the insertion therein of a receptor factor which is positioned relative to the male-fertile allele so as to allow the male-fertile allele to condition male fertility in the absence of the suppression factor and to prevent expression of male fertility in the presence of the suppression factor;
• pollinating plants of the first line with pollen from the plants of the second line and harvesting the seed produced in the plants of the first line;
• cultivating said seed to produce male-sterile mature maize plants;
• pollinating said male-sterile plants with pollen from male fertile plants of a selected third maize line;
• and
• harvesting the seed produced in the male-sterile plants.

Maize seed which upon cultivation will yield genetically stable male-sterile maize plants, comprising, in its genome:

• a suppression factor capable of actuation of a receptor factor elsewhere in the genome;
• a male-sterile allele;
• and
• an insertion mutated male fertile allele allelic with the male-sterile allele and mutated by the insertion therein of a receptor factor located relative to the male-fertile allele so as to prevent expression of male fertility in the presence of the suppression factor and to allow male fertility in the absence of the suppression factor.