Cytoplasmic male sterility (CMS), is a maternally inherited trait that inhibits production of viable pollen. It has been found in more than 150 plant species. CMS has been extensively utilized for hybrid production in major crops, e.g. maize, sorghum, rice, rapeseed, etc. However, even though the first CMS system, harknessii CMS (CMS-D2) was released in the early 1970s, no commercial cotton hybrids were produced by this CMS system in the US. Therefore, a new CMS system is needed.