Phenotypic Characterization and Diversity Analysis of a Collection of Gladiolus Cultivars in India using Morpho-physiological Traits

Abstract

Gladiolus is a beautiful ornamental geophyte valued for varieties with attractive florets and various colors. The genetic diversity of Gladiolus is tremendous due to species richness, outcrossing nature and heterozygosity. In the current study, phenotypic characterization and diversity assessment of 84 Indian and exotic-bred genotypes were investigated. Among different quantitative and qualitative traits, the coefficient of variation varied from 7.90% (androecium length) to 48.23% (chlorophyll ‘b’). All qualitative characteristics were polymorphic. In correlation analysis, 136 out of 253 pairwise inter-trait combinations revealed significant and positive correlations, although a significant and negative connection was found between the duration of flowering and the time of the beginning of flowering. Indirect selection for plant height, rachis length, and corm fresh weight may aid in the development of the linked traits. Principal component analysis revealed that six out of the 17 principal component axis had Eigen-values greater than one, accounting for 79.31% of the overall variability. The stable expression and better performance of Gladiolus genotypes for quantitative traits, such as plant height, length of the leaf blade, corm fresh weight, floret length, tepal length, and floret width would be useful in selection of superior offspring from hybridization. Cluster analysis divided whole germplasm into two major clusters: cluster I (29 genotypes) and cluster II (55 genotypes). Genotypes observed in subcluster Ia (08 genotypes) and subcluster IIc (13 genotypes) are relatively dissimilar from one another. Cultivar’ Victor’ is found to be relatively distinct among all genotypes because of taller plants, bigger corms, short flowering duration, and maximum corm fresh weight. Therefore, these set of genotypes can serve as a reference collection for DUS testing of novel varieties and genotype-specific information generated from this study can be useful for breeders to claim protection for their varieti