Essential oil yield and stability of various Rosa damascena Mill Landraces under different ecological conditions

Abstract

Essential oil production is the main objective of Damask rose (Rosa damascena Mill.) cultivation in many areas of the world e.g. Bulgaria, Turkey, India etc.,3 thus, essential oil is the most important trait in this crop. Besides its application in aromatic industries, some valuable characteristics of rose oil such as anti-HIV, antibacterial and antioxidant activities have been demonstrated recently.4,5 Essential oil is a complex trait, which is depended on yield components and is influenced by many genetic as well as environmental factors. Therefore evaluating of genotypes potential in different environments (location and years) is the important step in breeding programs of Damask rose before selecting desirable ones to commercial cultivation. A desirable landrace is one that does not only essential oil well in its area of initial selection but also maintains the high yielding ability over a wide range of environments. To identify such genotypes stability analysis is a good technique that measures the adaptability of different crop varieties to varying environments.6 Since, the literature on the effects of genotype environment compatibility and stability are low in Rosa damascena, inevitably, should refer to the methods used in similar plants. Eberhart & Russell1 model has widely used for evaluating of yield stability in both annual and perennial plants same as Campanula rapunculoides,7 Hevea brasiliensis8,9 and Thea sp10 Eberhart & Russell1 considered a stable genotype to have a slope (b value) equal to unity and deviation from regression (Sd) equal to zero. Freeman11 and Bernardo12 described the Eberhart & Russell1 model as the most widely used methods for evaluating of yield stability among main classical parametric methods that determine general and specific dynamic stability (adaptability) and measures linear and nonlinear components of stability. Furthermore, multivariate methods of stability such as AMMI, while statistically more complex, despite of widely uses in annual plants, has no advantages over the conventional methods in perennial crops and forest trees and its application is limited.13,14 We were also interested to know the contribution of each genotype in genotype×environmen (GE) interaction sum of squares. To do this, there are two stability parameters of Wricke’s15 ecovalence (Wi) and Shukla’s 2 stability variance (σi 2) which give the same results for ranking genotypes.16 Shukla2 the stablility variance of genotype as its variance across invironments after the main effects of environmental means have been removed. He used stability variance (σi 2) to estimate a component of the GE interaction corresponding to each genotype. According to his model, genotypes with a low σi 2 have smaller deviations from the mean across environments and thus more stable. A significant departure of a genotype’s regression coefficient from zero will be indicated by a large stability variance. The existence of genetic variation in responses to environmental changes among genotypes or significant genotype×environment (GE) interaction is the primary basis for stability analysis. Considerable variation among Iranian Damask rose populations has been reported for many traits such as morphological, oil content and flower yield.3,17,18 Results of some researches19,20 showed environmental effects on the quality and quantity of flower and essence yield. Nirmal & Sushil Kumar21 also introduced Ranisahiba landrace of Damask rose with relative higher essential oil and stable for some morph-physiological traits. Despite the existence of relatively high essential oil landraces of Damask rose, stability and adaptability are important. This study was carried out