Assessment of genetic diversity in glandless cotton germplasm resources by using agronomic traits and molecular markers

Seventy-one glandless cotton germplasm resources were firstly evaluated genetically by using nine agronomic traits, 33 simple sequence repeat (SSR) primers and ten amplified fragment length polymorphism (AFLP) primer combinations. Principal component analysis (PCA) of the agronomic traits showed that the first six principal components (PCs) explained a total of 86.352% of the phenotypic variation. A total of 329 alleles were amplified for 33 SSR primers, and 232 polymorphic bands in a total of 389 bands were obtained by using ten AFLP primer combinations. The average polymorphic information content (PIC) value was 0.80 and 0.18 for SSR primers and AFLP primer combinations, respectively. The DIST (average taxonomic distance) and DICE (Nei and Li’s pairwise distance) coefficients ranged from 0.373 to 3.164 and 0.786 to 0.948, respectively, for agronomic traits and SSR&AFLP data based on UPGMA analysis. This suggested that there was a higher diversity in the evaluated population for both agronomic traits and molecular markers. The Mantel’s test showed that the correlation between the dendrograms based on agronomic traits and SSR&AFLP data was non-significant.