Adaptation and yielding ability of castor plant (Ricinus communis L.) genotypes in a Mediterranean climate

Successful castor (Ricinus cammunis L.) cropping in Greece depends on the yielding ability and yield stability of the cultivars (hybrids or inbreds) as well as the reliability of production systems. The adaptation and yielding ability of 19 modern castor oil genotypes were studied for 3 years in two sites of Northern Greece. Genotypes combining high seed and oil yield and desirable morphological characteristics were tested for 2 or 3 years, whereas the rest were tested for 1 year only. The growing period in both locations was long enough for ripening the first raceme and a number of secondary racemes depending on the genotypes. The plant height was dependent mainly on the genotypes but also was affected by the site and the year of the experimentation and ranged from 79 to 278 cm. The seed yield varied between 2.5 and 5.0 Mg ha(-1), values that are among the highest reported in the literature. The seed yield was higher in the site where plants produced and ripened more secondary racemes. The seed oil content was dependent mainly on the genotype and ranged from 44.5 to 54.2%. The oil yield followed the changes in seed yield. The variation in seed yield between years was low and in most genotypes less than 20%. Results indicate that the castor oil crop was satisfactorily adapted in the area. (C) 1999 Elsevier Science B.V. All rights reserved.