Genetic divergence in Capsicum annuum L. under protected conditions based on new DUS descriptors

A comprehensive three-year pioneer study to develop DUS descriptors of Capsicum annuum under protected conditions was undertaken that defined 56 morphological descriptors and were utilized for genetic divergence analysis. The study revealed substantial phenotypic variability across plant, leaf, floral, fruit and seed traits, with the Shannon Diversity Index (H') ranging from 0.09 to 1.57. High variability was recorded for length of first internode (H' = 1.57), pericarp thickness (H' = 1.43), fruit shape (H' = 1.38), plant height (H' = 1.24), fruit length (H' = 1.21) and fruit stalk length (H' = 1.10), indicating broad allelic diversity and strong potential for breeding interventions. Bell pepper genotypes demonstrated high variability in locule number (H' = 1.10). The population was dominated by key traits, including thin pericarp (41.38%), long stalk length (50.00%), dentate calyx margins (86.21%), constricted calyx (91.38%), strong pedicel attachment (62.07%), presence of blossom-end appendage (93.10%), medium maturity (50.00%), heavy seed weight (> 6.0 g) and generally low seed recovery efficiency (65.52%). The genotypes were classified into ten distinct clusters using Tocher's method, where clusters clusters I, II, IV, VII, VIII and X comprised hot pepper and paprika genotypes, while clusters III, V, VI and IX comprised bell pepper genotypes. Principal component analysis revealed that the first four principal components explained most of the existing variation (> 70%) in the germplasm. Overall, the substantial diversity observed across traits highlights the genetic potential of the evaluated Capsicum genotypes as a valuable resource for crop improvement, conservation and targeted breeding of desirable morphological and agronomic traits.