Maternal Inheritance and Maternal Effects

Hybrid seed production: an applied usage of maternal inheritance

• Takes advantage of heterosis

Heterosis - the phenomenon were the phenotypic value of the heterozygote is greater than either of the two parents; with plants same species such as corn exhibit heterosis for yield

• Heterosis requires preventing self-fertilization; originally manual detasseling of the female parent was required to prevent self-pollination.

• Nuclear genes contolling male sterility were first investigated, but proved to be inefficient, because of a portion of the population was always fertile
  
• The ultimate solution to this problem was the use of cytoplasmic male sterility (cms).
  
• Because fertile seed must be produced by the farmer, the hybrid must be fertile. This required restorer of fertility (Rf) genes.
  
• These dominant nuclear restorer genes can override the cytoplasmic male sterility factors. These plants that have the cms cytoplasm, but contain a dominant Rf allele will be male fertile.