GENETIC ANALYSIS OF SOME ROSES CULTIVARS APPROPRIATE FOR S-E ROMANIA CLIMATE USING PCR - ISSR TECHNOLOGY

Abstract

Current cultivated roses varieties were obtained through intensive cross-breeding between a limited number of species of genus Rosa (about 8 to 20 from 200 wild species) and for many of them there are no accurate information about their genealogy. The present study aims to determine the genetic diversity of 10 rose varieties, from Botanical Garden of Bucharest collection, which are not included in the official list of rose varieties from Romania, according ISTIS. Choosing these cultivars started from the need to identify rose varieties resistant to the climate in SE Romania with extended summer drought and winter frost. A number of 86 individuals were genotyped using PCR-ISSR technique. From a total of 23 tested ISSR primers, 11 were selected due to their capacity to produce informative band patterns. These primers generated 292 ISSR markers, with a mean of 26.54 bands/primer and a polymorphism percentage of 96.025%. The average values of polymorphic information content (PIC), resolving power (Rp) and marker index (MI) proved the discriminatory power of ISSR markers (i.e PIC varied between 0.22 and 0.43 and Rp between 7.81 and 17.2). Genetic diversity as revealed by Shannon index (I=0.45±0.0734), genetic differentiation index (GST=0.027) and estimate of gene flow (Nm=16.982) is relatively high. The AMOVA analysis showed that 67.36% of the total genetic variation resides within cultivars, which is similar with other shrub species. The UPGMA dendrogram built on ISSR markers grouped the 10 cultivars in two major clusters according with their origin and some of their phenotype characteristics. ISSR fingerprinting proved to be appropriated for the quantification of the level of genetic variation in the selected cultivars.