Genetic diversity analysis and molecular characterization of tropical rose (Rosa spp.) varieties

Abstract

Characterization of rose varieties becomes essential for understanding, utilizing, and preserving the diversity among them, for their genetic improvement, cultivation, and conservation. With this purpose, 19 tropical rose varieties were evaluated via quantitative morphological and molecular markers. A significant degree of variation was observed across nearly all descriptors, suggesting a notable level of genetic diversity among the released rose varieties. Traits like flower diameter, flower yield/plot, and shelf life, considered to be of vital importance given the aesthetic value of rose, exhibited remarkable differences that would further aid in the selection of desirable varieties. The maximum flower diameter, flower yield/plot, and shelf life were recorded in Yellow Page, Lambada, and Delhi Princess, respectively. The varieties were evaluated by correlation matrix, hierarchical agglomerative clustering method-based dendrogram, network plot on phenotypic correlation, colour intensity graph including Red-Green-Blue (RGB) scattered plot. In the correlation matrix, it was found that more number of primary shoot contributes to higher flower yield, while increase in leaf area degraded the shelf life of the flower. Realizing the importance of molecular characterization, 10 selected polymorphic inter simple sequence repeats (ISSR) and start codon targeted (SCoT) polymorphism primers were tested that amplified total 187 polymorphic loci with 94.4 % polymorphism. Cent percent polymorphism were found with SCoT-2, SCoT-18, SCoT-19, HB-12 and ISSCR3 primers. A principal component analysis based on molecular diversity highlighted that First Red, Local Selection 2, and Himroz exhibited distinct characteristics compared to the other varieties. The 19 varieties were grouped into 8 clusters viaunweighted pair group method with arithmetic mean-based dendrogram at 0.4 similarity co-efficient. The analysis revealed a significant genetic distance between Himroz, First Red, and Grand Gala, suggesting their potential to be utilized in hybridization programs for crop improvement. The distinguishable genetic background and high degree of variation revealed by molecular markers, specifically ISSR and SCoT, offer valuable insights that can contribute to the strategic improvement of roses. These findings provide a foundation for expediting rose breeding programs and comprehensive crop improvement strategies.