Genetic diversity, redundancy and population structure in flax (Linum usitatissimum L.) as revealed by dominant molecular marker system

In the present investigation, RAPD profiling was employed to estimate the genetic diversity, population structure and linkage disequilibrium in 232 flax germplasm which were divided into three population viz. CRIJAF population, NBPGR population and CSKHPKV population based on their source of collection. The RAPD markers generated total 122 allele out of which 72 showed polymorphism (61.83 %) with mean effective number of allele, PIC, MI, RP value as 1.14, 0.13, 21.39 and 1.59 respectively. The RAPD primers also exhibited the highest Nei's gene diversity (h) and Shannon's diversity index (I) in CRIJAF population (h = 00.116 and I = 0.206) followed by CSKHPKV and NBPGR population, with a low level of overall genetic variability (h = 0.107 and I = 0.187). AMOVA illustrated that 14% of the total genetic variability was originated due to inter population whereas the remaining 80% of the total variability arose within the populations. The overall relative magnitude of genetic differentiation among the populations was 0.15 and also high level of gene flow between the populations was observed. The results of population structure analysis proposed that total flax accessions were distributed into nine genetic groups. Phylogenetic tree also successfully identified the redundant genotypes from the total flax accession. LD analysis indicated narrow inter-population genetic variation and higher level of intra-population genetic variation in flax. The findings of the present investigation will be helpful for utilization of flax germplasm in future crop improvement programme and association mapping.