AROMA AS A FACTOR IN THE BREEDING PROCESS OF BASIL

Abstract

Sweet basil is one of the main herbs grown in the Mediterranean region. The market and the growers have been requesting breeders to provide rapid solutions to urgent problems, such as resistance to diseases or tolerance to chilling. Naturally, as has happened in other crops, there is the danger that this process is leading to high yields, nice appearance and good shelf life, but with the loss of aroma and flavor quality. In the case of basil, crossing between varieties could yield a new type of aroma, and even new compounds that do not exist in the parent plants. Here we present a few examples of such changes. Case 1: Variation is necessary for selection, but could be problematic in the case of the aroma when it is not the target trait to improve. When there is internal variation of the volatiles composition in the source population, any selection may lead to genetic lines with different types of aroma. In the second case we demonstrate crossing between two cultivars of basil that differ in their aromas. The cultivar 'Cardinal' is a methyl chavicol type and the cultivar 'Perrie' is a eugenol type. In the F 2 generation we obtained about 35% typical Eugenol type plants like 'Perrie' and 15% of phenylpropenes composition similar to 'Cardinal'. The others had intermediate composition of eugenol, chavicol and methyl chavicol. Moreover, fenchol and fenchyl acetate are microcomponents in 'Cardinal' and do not exist at all in 'Perrie'. Actually, they are undesirable compounds in the edible basil. In addition to the expected result that part of the F 2 plants contain one or both of these components, some of them contain the component fenchone that did not exist in either parent. The conclusion of these results is that the breeder should learn more about the composition of the aroma compounds, analysis methods, biochemistry and the mode of inheritance, in order to include the aroma factor in the breeding program and to consider it during the entire process.