AbstractThe expression ofcmsin chives is controlled by a cytoplasmic factor (5), a restorer geneX/x(Tatlioglu1982) and a temperature geneT/t(Tatlioglu1987). In recent investigations (Tatlioglu1986) it could be shown that tetracycline also influences the expression of 0731. To obtain information about the genetic control of tetracycline sensitivity ofcms, tetracycline‐sensitive and tetracycline‐insensitivecmsplants were crossed with each other as well as with maintainers and the reaction of their progeny to tetracycline base was investigated.The results indicated that the promotion of fertility due to high‐temperature conditions (24°C/24 °C, day/night) and tetracycline · base are independent of each other. The results of crosses can be explained by a nuclear gene,A/a, causing the tetracycline sensitivity when recessive. By using different genotypes of the three loci for restoration, temperature and tetracycline sensitivity highly advantageous material can be constructed for the investigation of the interaction between the nuclear and the mitochondrial genome in higher plants, for the molecular and functional basis ofcmsand for its use in plant