Genetic diversity spectrum and marker trait association for agronomic traits in global accessions of Linum usitatissimum L.

A thorough understanding of genetic diversity in Linum usitatissimum L. will equip scientist to address ever expanding breeding challenges in the species. Present study was undertaken to assess the genetic diversity and marker trait association analysis using 130 Linum usitatissimum L. accessions of diverse geographic origin (75 exotic, 55 indigenous), by employing 26 morpho-metric (11 qualitative and 15 quantitative) traits along with 22 simple sequence repeat (SSR) markers including 07 expressed sequence tagged-SSR (EST-SSR) and 15 genic SSR (gSSR). In the study high estimates of variability were recorded for seed yield per plant (85.12%) followed by fibre weight per plant (69.24%). Fibre weight per plant was found significantly correlated with plant height and days to flowering while seed yield per plant had significant but negative association with plant height and fibre weight per plant. First four principal components explained a total of 98.98% of the morphological variations. Fifteen gSSR markers produced 47 polymorphic bands with mean polymeric information content (PIC) value 0.326 whereas, seven EST-SSR markers (13 bands) recorded lower mean PIC value (0.245). Quantitative traits based clustering grouped all accessions into six groups. Clustering based on individual markers was neither according to origin nor morphotypes. Finally, clustering using all markers together (Morphological + EST-SSR + gSSR) divided flax type and linseed type accessions into separate groups. Pooled markers based clustering well supplemented by Nei's genetic distance. Multiple regression analysis using all markers together revealed 95 polymorphic marker alleles (gSSR: 48, EST-SSR: 10 and morphological markers: 37) associated with one or more quantitative traits. For fibre weight per plant 11 marker alleles were found associated and explained 62.4% of variations. However, finding of the present study can be further strengthened with inclusion of more number of markers putatively associated with economically important traits.