Genetic Diversity and Population Structure Analysis to Construct a Core Collection from Safflower (Carthamus tinctorius L.) Germplasm through SSR Markers

Genetic resources are the fundamental source of diversity available to plant breeders for the improvement of desired traits. However, a large germplasm set is difficult to preserve and use as a working collection in genetic studies. Hence, the present study evaluates the genetic diversity of 3115 safflower accessions from the Indian National Gene Bank, including Indian cultivars, to develop a manageable set of accessions, with similar genetic variations of germplasm studied. A total of 18 polymorphic SSR markers were used. The genetic diversity analysis revealed that germplasm accessions were highly diverse and there is no correlation between genetic diversity and the geographical collection of germplasm or sourcing of germplasm. A core set was developed using a core hunter software with different levels of composition, and it was found that 10% of the accessions showed maximum gene diversity and represented an equal number of alleles and major allele frequency in the germplasm studied. The developed core consisted of 351 accessions, including Indian cultivars, and they were validated with various genetic parameters to ascertain that they were a true core set for the studied accessions of safflower germplasm.