Cytoplasmically male-sterile flue-cured cultivars that were derived by backcrossing normal male fertile cultivars to a male-sterile one containing either Nicotiana suaveolens or Nicotiana glauca cytoplasm were investigated. The N. suaveolens cytoplasmic source of cytoplasmic male sterility (cms) has been used on a global basis for hybrid seed production for many years. This source of cms was initially chosen because it resulted in little if any agronomic penalties in a cultivar's performance. The only apparent penalty is production of abnormal styles and stigmas under stressful growth environments. The use of the N. glauca cms system showed a significant improvement in the frequency of normal flowers and the number of seed per capsule from plants grown under similar stress conditions. Field trials of isogenic lines in N. tabacum , N. suaveolens and N. glauca cytoplasms showed no negative effects on leaf yield and quality for either male-sterile cytoplasm. The investigation of additional male sterile cytoplasm sources is an important step in reducing the potential genetic vulnerability of the crop and improving the efficiency of hybrid seed production.