In order to evaluate flower yield and essential oil content of Rosa damascena, 49 landraces were studied in a randomized complete block design with three replications in Sanandaj (Iran) during 2004-8. An analysis of variance revealed significant differences (p ≤ 0.01) for the number of flowers per plant, flower and petal weight, flower and petal yield per plant, essential oil ratio and essential oil yield per plant among landraces (G), years (Y) and for landrace × year (GY). The landraces of FA1, KR2, KR3, FA2, AR1 and YZ2 with 3291.9, 2526.4, 2298.7, 2239.8, 2077.6 and 1978.7 kg ha−1, respectively, produced the highest flower yield and the landraces of IS3, IS2, KR2, IS4 and FA2 with 413.25, 378.11, 364.31, 315.30 and 296.10 g ha−1, respectively, produced the highest essential oil among all of the landraces. In accordance to this, cluster analysis also classified high flower and essential oil yield landraces in distinct groups at an 87% similarity. According to the results, most landraces that originated from temperate, warm temperates and arid regions such as the FA2, YZ2 and Isfahan group of landraces produced higher flower yield and essential oil than those from cool, cool temperate, semi-arid and humid regions. Taking into consideration flower yield and essential oil, the landraces of KR2, YZ2, IS3, IS2 and FA2 with 2526.4, 1978.7, 1659.8, 1663.2 and 2239.8 kg ha−1 flower yield, respectively, and 364.31, 265.31, 413.25, 378.11 and 296.10 g ha−1 essential oil, respectively, produced the highest flower yield and essential oil content among the landraces and are recommended for semi-temperate and cool areas.
