Segev, D., Division of Aromatic and Medical Plants, Newe ya'Ar Research Center, Agricultural Research Organization, P.O. Box 1021, Ramat Yishay, Israel
Nitzan, N., Division of Aromatic and Medical Plants, Newe ya'Ar Research Center, Agricultural Research Organization, P.O. Box 1021, Ramat Yishay, Israel
Chaimovitsh, D., Division of Aromatic and Medical Plants, Newe ya'Ar Research Center, Agricultural Research Organization, P.O. Box 1021, Ramat Yishay, Israel
Eshel, A., Department of Plant Sciences, Tel Aviv University, Tel Aviv, 69978, Israel
Dudai, N., Division of Aromatic and Medical Plants, Newe ya'Ar Research Center, Agricultural Research Organization, P.O. Box 1021, Ramat Yishay, Israel

Populations of Mentha longifolia, an endangered species in Israel, were tested for essential oil composition and conservational ability. In 2002-2003, 25 wild populations country-wide were tested, indicating population divergence into two chemotypes. Chemotype A was characterized by high levels of menthone and pulegone, and chemotype B by high levels of piperitenone oxide and piperitone oxide. Chemotype A was more abundant (22 of 25 populations) than chemotype B (11 of 25 populations). However, a chemotype/population interaction was not recorded (P > 0.05). In spring 2003, seven of the 25 wild populations were resampled, propagated, and cultivated at the Newe Ya'ar campus. Then, in 2004, the propagated plants were tested for essential oil composition. The propagated plants maintained the essential oil composition as well as the chemotype-frequency distribution of the original wild population from which they were obtained. Since a chemotype/population interaction was not recorded, and the cultivated plants displayed the wild population essential oil composition, it can be concluded that i) the chemotype diversity is genetically based, and ii) the M. longifolia populations sampled can be horticulturally conserved. Copyright © 2012 Verlag Helvetica Chimica Acta AG, Zürich.