گزينش همزمان براي افزايش عملكرد گل محمدي (Rosa damascena Mill.) در شرايط اقليمي تهران

Simultaneous Selection for High Yield in Rosa damascena Mill, under Climatic Conditions of Tehran

Simultaneous selection is an efficient method of obtaining superior genotypes. An experiment was undertaken for a duration of 3 years to evaluate 40 Damask rose accessions for higher yield performance, using a 3 times replicated randomized complete block design at the experimental field of Research Institute of Forests and Rangelands, Tehran, Iran. Different traits were simultaneously taken into consideration. For all the traits variation found among the tested entries was highly significant (P<0.01) with most of the traits showing high heritability (h2b). Using phenotypic and genotypic variance as well as covariance matrices and broad sense heritability as the relative economic value, selection indices were estimated. The results indicated that selection based on all of the traits (index 12) would end up with more gain. Based upon the calculated coefficients for each index, indices No. 11, 10, and 7 indicated maximum genetic gain following index No. 12. Regarding the expected response to selection for different traits in each of the indices, flower number was considered as the most appropriate trait. Also, based upon the present indices, the highest selection indices were obtained for Ilam l, Khorasanl, Kermanshahl, Khuzistanl, Fars2, Qazvinl, Yazd2, and Isfahan 8 accessions. Thus, they could be used as superior accessions for flower production or as the parents of new varieties in the study area or in environments similar to it.