Document Type : Research Paper

Authors

• Homayon Kheyri ¹
• Alireza Rajabi Mazhar ¹
• Fatemeh Salimi ¹
• Seyed Reza Tabaei-Aqdai ²
• Mohamad Souri ³
• Javad Hamzei ⁴
• Nasim Shabani ¹

¹ Research Division of Natural Resources, Hamedan Agricultural and Natural Resources Research and Education Center, AREEO, Hamedan, Iran

² Research Institute of Forests and Rangelands, Agricultural Research, Education and Extension Organization (AREEO), Tehran, Iran

³ Research Division of Agricultural and Horticultural Plants, Hamedan Agricultural and Natural Resources Research and Education Center, Agricultural Research, Education and Extension Organization (AREEO), Hamedan, Iran

⁴ Department of Plant Production and Genetics, Bu-Ali Sina University, Hamedan, Iran

Abstract

Background and objectives: The damask rose (Rosa damascena Mill.) belongs to the Rosaceae family and has been cultivated in Iran for many years for the production of rose water. It is highly valued for its medicinal properties and is often referred to as “fragrant gold.” Damask rose essential oil, extracted from its flowers, is among the most valuable and expensive essential oils in the world. Notably, damask rose exhibits considerable genetic diversity, which influences important traits such as flower yield per plant, number of flowers per plant, flower weight, essential oil quality, flower color and shape, and resistance to diseases and environmental stresses. Identifying these variations among different genotypes can help improve crop yield and quality. This study compares rose genotypes from various origins to identify desirable traits for different ecological regions, evaluating the effects of genetic and environmental factors, trait stability, and adaptation to diverse conditions. Ultimately, the goal is to identify superior rose varieties with optimal flower and essential oil yields suitable for the cold semi-arid climate of Hamedan.
Methodology: In this experiment, 41 genotypes of Rosa damascena Mill., collected from different parts of the country, were cultivated in a randomized complete block design with three replications at the Ekbatan Research Station, located at the Agricultural and Natural Resources Research Center of Hamadan. Each genotype was evaluated under uniform management conditions without the application of specific stress treatments. Since flowers are the economic organ and the main source of active compounds in damask rose, several traits were recorded to identify cultivars compatible with the ecological conditions of Hamadan and capable of producing higher flower yields. These traits included flower yield per plant, number of flowers per plant, number of petals per flower, percentage of dry matter in flowers, fresh weight of petals per flower, ratio of fresh petal weight to total flower weight, flowering duration, plant vigor, plant height, and canopy diameter. Measurements were recorded over three growing seasons from 2006 to 2008. Finally, the data collected were analyzed using PAST, SPSS, and SAS software.
Results: The analysis of variance for the traits studied revealed highly significant differences among genotypes for all traits. Genotype, year, and the genotype × year interaction had a significant effect on flower yield and number of flowers per plant at the 1% probability level, and on plant height and canopy diameter at the 5% probability level. In addition, the effects of genotype and year on fresh petal weight per flower, plant height, and canopy diameter were significant at the 1% probability level. Factor analysis indicated that the first factor, as the principal factor, explained about 98% of the total variation. Within this factor, the number of traits, flowers per plant, and flower yield per plant showed positive loadings, reflecting the high diversity among genotypes. Furthermore, the results of principal component analysis confirmed the grouping obtained from cluster analysis; the three groups identified by cluster analysis were clearly distinguished in the principal component analysis. The genotypes in the second group, including Isfahan 8, Isfahan 6, Tehran, and Yazd 2, were identified as superior genotypes. Moreover, a positive and significant correlation was observed between the number of flowers per plant and fresh petal weight per flower with flower yield per plant. Among these traits, the number of flowers per plant had the greatest direct effect on flower yield per plant. Therefore, these traits can be considered as important selection criteria for improving flower yield in damask rose genotypes.
Conclusion: This study demonstrated considerable genetic diversity among damask rose genotypes and highlighted the important role of yield-related traits in the selection of superior genotypes. The number of flowers per plant was identified as the most influential trait affecting flower yield and can be used as a primary selection criterion in breeding programs. The genotypes Isfahan 8, Isfahan 6, Tehran, and Yazd 2 are recommended for cultivation under the semi-arid and cold climatic conditions of Hamedan due to their high performance and adaptability.

Keywords

• Damask rose
• adaptability
• genotype
• flower yield
• Hamadan

Main Subjects

• Improvement and breeding