The production of cis-abienol, a leaf surface diterpene of tobacco (Nicotiana tabacum L.), was confirmed to be genetically controlled by a single dominant gene in the cross between cis-abienol producing Red Russian and non-producing HM 195. To identify the chromosome carrying the gene designated as Abl, crosses were made between each of seven monosomics of Red Russian, Haplo-A, -B, C, -E, -F, -H, and -K. and HM 195 or TI 245 as the pollen parent. An examination for cis-abienol production in the seven F₁ populations showed that only the F1 of Haplo-A × HM 195 included plants not producing cis-abienol. The percentage of such plants was approximately equal to the ovular transmission rate of Haplo- A. Cytological examination of plants from the cross of Haplo-A × HM 195 revealed the association of the monosomic state with the deficiency of cis-abienol production. These results demonstrated that the gene for cis-abienol production in tobacco is located on chromosome A.

(Full article published with kind permission from "Tobacco International")