To determine the mode of inheritance of citral, linalool, methylchavicol, and methylcinnamate in basil, controlled crosses were made between chemotypes rich in each of these constituents. Four stable Ocimum basilicum populations selected for high methylcinnamate (79%), methylchavicol (95%), linalool (82%), and citral (65%) respectively, served as parents. Crosses were made using chemotypes rich in terpenes (linalool × citral), in phenylpropanoids (methylchavicol × methylcinnamate), and a third that combines chemotypes from both biosynthetic pathways (linalool × methylchavicol). True hybrids were selfed in isolation and one hundred F2 plants were analyzed for their oil composition. The parents, the F1 hybrids and the F2 generation of all plants were evaluated in a field trial under identical environmental conditions. Plants were harvested at full flowering, and dried at 380 °C. Identification of essential oil constituents were confirmed by GC/MS. The F2 segregation data for each major oil constituent trait will be examined by c2 analysis tests. Preliminary results indicate that methylcinnamate segregates in a 3:1 ratio, and is a dominant major gene. In the two crosses using methylcinnamate chemotype as a female parent, the F2 population segregates in 80:22 and 65:28 methylcinnamate:non-methylcinnamate plant types, with P = 0.42 and 0.25 and c2=0.64 and 1.29, respectively. Analysis of the other crosses are being processed, evaluating qualitative and quantitatively the presence or absence of each constituent in their F2 population.
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