Genetic variability and population structure in a collection of inbred lines derived from a core germplasm of castor

Abstract

Castor (Ricinus communis L.) is an industrially important oilseed crop and is the only source of an unusual fatty acid, ricinoleic acid in plant species. The castor oil and its products have numerous industrial uses including biofuel; hence, the demand for castor oil is ever increasing globally. Current productivity levels in castor are inadequate to meet the requirement, which underscores the need for breeding high yielding cultivars with better adaptability by exploiting diverse genetic resources. This study reports development and characterization of a set of inbred lines derived from a core germplasm collection of castor. The panel of 144 inbreds exhibited an excellent phenotypic diversity for morpho-agronomic traits related to plant architecture and yield components. However, SSR allelic diversity appears to be only moderate. The average number of alleles per SSR locus in the genotype panel was 3.0 and mean gene diversity was 0.38. Nevertheless, a majority of the inbred pairs (77 %) had very less estimated kinship coefficients (<0.05) suggesting that they were not related by pedigree. A very low level of genetic relatedness among the genotypes and absence of population structure suggest that this genotype panel consists of ideal set of materials for association mapping studies aiming at molecular breeding of key traits in castor. To our knowledge, this is the first report on the development and characterization of a large inbred collection representing the bulk of genetic diversity in castor, which can be further exploited for genetic, physiological and molecular studies towards achieving higher productivity.