A Study of Morphological Variations and Their Relationship With Flower Yield and Yield Components in Rosa Damascena

Rosa damascena has attracted considerable attention in horticulture, biochemistry andin pharmacology because of the fragrance of the flowers and the high content of its biologicallyactive substances. there is limited information available on factors controllingflower yield and its components. the present study reports an investigation on floweryield and the various factors affecting it, in iranian rosa damascena using sixteen genotypescollected from different regions in iran. these genotypes were planted at isfahanagriculture research center, using a randomized complete block design with three replicationsin 2005. twelve yield determining characters including flower yield per plant,number of flowers per plant, fresh flower weight, plant height, canopy diameter, lengthand width of bud, number of petal per flower, length and width of receptacle, freshweight of petal as well as flowering period were recorded. rosa damascena genotypes significantlyvaried for all the traits except for the fresh weight of petals per flower. phenotypicand genotypic coefficients of variation for flower yield per plant (48.03%, 36.49%),number of flowers per plant (40.65%, 26.99%), number of petals per flower (37.56%,32.31%) were higher than the coefficients for other tested traits. cluster analysis revealedthat khuzestan and shiraz 2 genotypes were the most related ones, while the most independentones were the western and eastern azerbaijan genotypes. results of stepwise regressionanalysis showed that 90 percent of total variation of flower yield per plant couldbe explained by the number of flowers per plant. this suggested that number of flowersper plant is the most important component determining flower yield per plant. accordingto principle component analysis, parents with a high standing of the following traits: freshweight of flower, number of petals per flower and bud width, may well be employed forhybridization in a breeding program. regression and cluster analyses proved to be theappropriate multivariate analyses for an identification of rosa damascena genotypes possessingthe desirable characters for hybridization to develop improved cultivars.