Restore gene is needed

Solution (By Examveda Team)

A restore gene is needed to bring fertility in the male sterile plant.
The restorer-of-fertility (Rf) nuclear genes have been used to rescue the damage induced by mitochondrial DNA rearrangements.
Rf is a dominant allele for restoring male fertility and rf is its recessive allele inducing male sterility, in the presence of a male-sterile cytoplasm, S. N refers to normal cytoplasm that gives male-fertile plants in the presence of either the Rf or rf allele in the homozygous state.