Trait-specific accessions in global castor (Ricinus communis L.) germplasm core set for utilization in castor improvement

Castor (Ricinus communis L.) is a non-edible industrial oilseed crop. Its oil has multiferous applications in industry. A vast castor germplasm collection of 3289 accessions is being maintained at ICAR-Indian Institute of Oilseeds Research, Hyderabad, India. The large size of castor germplasm has become a problem for evaluation, conservation and utilization. Hence, a core-set comprising 165 accessions representing diversity in the entire collection was developed. Though the core set is genetically diverse, its utilization in breeding programme is not picking up because of its still large size. In order to enhance efficacy of core set, an attempt was made in to identify core set accessions possessing resistance to major biotic stresses such as Fusarium wilt, root rot, gray mold and leafhopper, and desirable qualitative and quantitative traits. Screening against biotic stresses was done under artificial infestation conditions in field and greenhouse/ploy house at multilocations over years. Evaluation for stability of quantitative and qualitative traits was done at multilocations under rainfed and irrigated conditions. This study has thus identified 26 core set accessions possessing resistance to wilt, root rot, gray mold and leafhopper, and high ricinoleic acid content, high yield and seed weight and early maturity. These accessions would serve as instant basic resources for utilization in breeding programmes to improve castor for resistance to major biotic stresses as well for yield, ricinoleic acid content and early maturity. They also play an important role in diversifying the genetic base of working collection of castor breeders for developing improved cultivars with broad genetic base.