The Genetic Basis for the Conversion of Menthone to Menthol in Japanese Mint.

HE major components of Mentha oils are a principal ketone, and its related alcohol and ester. Since these compounds account for 75-85 percent of the oil by weight, an elementary genetic understanding of their origin and relationship would seem important to any plant breeding work. In this paper, we wish to consider the genetic relationship between the ketone (menthone) and its related alcohol (menthol), using Mentha aruensis L. var. piperascens Briq. 2n = 96 (Japanese mint) as the low menthone-high mentho1 parent. For a high menthone-low menthol parent (nonmentliol by odor), we chose fertile menthone-odored SI strains of either M . spicata L. (2n = 48) or M . crispa L. (2n = 48). Most So strains of these species have carvone and a spearmint odor. MURRAY and REITSEMA (1954) have shown that carvone ( C ) is dominant to menthone ( c ) . SIEVERS, LOWMAN, and RUTTLE (1945) have previously reported that Japanese mint crossed to M . spicata L. gave several hybrids having menthol, and they further investigated the commercial value of these plants. Recently, hybrids of this cross have been studied by IKEDA and UDO (1957). They found menthol hybrids and also hybrids with carvone, the ketone of spearmint. While segregation was known to exist in these interspecific hybrids, a genetic analysis had not been undertaken.