Genetic Diversity Analysis and Barcoding in Tuberose (Polianthes tuberosa L.) Cultivars Using RAPD and ISSR Markers

Abstract

Tuberose is one of the most important bulbous ornamentals grown commercially for loose as well as cut flowers. RAPD and ISSR markers used in the study revealed 53% and 73% polymorphism, respectively, among ten tuberose varieties. Polymorphic Information Content (PIC) and Resolving Power (RP) for RAPD varied from 0.35 - 0.46 and 0.8 - 3.6, respectively, and that for ISSR was 0.36 - 0.49 and 0.91 - 4.55, respectively. The dendrogram (UPGMA), based on Jaccards co-efficient as similarity index for RAPD and ISSR, grouped ten varieties into two major clusters, and, combined RAPD-ISSR cluster analysis formed three major clusters based on their genetic relatedness/variation. PCA revealed that the spatial arrangement of these 10 cultivars was congruent with dendrogram analysis. Mantel's test indicated very good correlation, with r = 0.86 for combination of ISSR and RAPD-ISSR. To facilitate identification of tuberose cultivars, a cultivar identification diagram (CID) was developed in which seven ISSR loci could differentiate all the ten cultivars used in the study. Barcodes were developed for five cultivars released by IIHR using 57 polymorphic loci generated by 11 ISSR primers. The size of these loci ranged from 252bp to 2.2kb. These barcodes can be used as a standard reference source for quick identification of cultivars.