Genetic diversity dissection and population structure analysis for augmentation of bread wheat (Triticum aestivum L.) germplasm using morpho-molecular markers

For wheat improvement, knowledge of diversity patterns and evolutionary relationships among the germplasm is essential for the sustainable conservation of valuable genetic materials. Therefore, this investigation aims to decipher the genetic diversity and population structure of wheat germplasm and identify diverse accessions to expedite the wheat breeding programs. In this study, a diverse set of 81 bread wheat genotypes, including derived doubled haploids, elite exotic lines, indigenous landraces and cultivars were used. Phenotypic and molecular characterization was conducted using 10 morpho-physiological traits and 68 microsatellite (SSR) markers, respectively. Among, the nine morphological descriptors the highest morphological variation (H) was observed for 1000 grain weight (1.06). The genotypes based on phenotypic traits were grouped into three clusters using Euclidian distance. Principal component analysis (PCA), revealed that the first four significant principal components accounted for 78% of the variance. A total of 58 alleles were generated from 27 polymorphic SSR primers with an average of 2.15 alleles per locus. The polymorphic information content (PIC) ranged from 0.26 (Wmc434) to 0.76 (Wmc47), with an average of 0.69. Molecular analyses by NTSYS-PC delineated the genotypes into four clusters, whereas while the cluster tree generated using neighbour-joining analysis identified three major clusters. Structure analysis grouped the genotypes into three sub-populations. When comparing agro-morphological and molecular clusters, seven genotypes (DH 194, DH 207, DH 215, DH 217, CIMMYT line 30 Entry No.10, Chamba landrace 18 and C 306) were identified as common. Notably, these genotypes were identified as distant and belong to different diversity clusters. Therefore, integrating morphological analysis with a polymorphic SSR survey may be effective in selecting diverse parental lines in wheat hybridization programs.