Comparative studies on several castor (Ricinus communis L.) hybrids: Growth, yields, seed oil and biomass characterization

• It presents growth and yields results for ten castor hybrids (provided by KAIIMA Company from Israel) when cultivated in Greece (2011, 2012 & 2014) and Italy (2014).
• Seed yields with yields up to 4.4 t/ha were recorded and higher yields can be achieved with the improvement of the cultivation practiced.
• This research work takes under consideration the whole use of the crop; its seeds for oil production as a source for the EU biobased industry and the remaining biomass as a source for solid biofuels.

For three growing periods (2011, 2012 & 2014) a total number of tencastor hybrids (Kaiima 71, Kaiima 75, Kaiima 93, C854, C855, C856, C 857, C864, C1002 and C1008) were tested in Greece (Aliartos; 2011, 2012 & 2014) and Italy (Cadriano; 2014) in order to compare the seed yields and straw production as well as to evaluate residual straw as solid biofuel. In Greece, the mean seed yields, was 2.77 t/ha and ranged from 1.68 t/ha (C865, 2012) to 4.27 t/ha (Kaiima 93, 2011). Correspondingly, the mean oil content of the castor seeds was 48.12% with a range from 45.5% (C1008, 2014) to 52.1% (Kaiima 75, 2011). In Italy, the mean seed yields was 2.46 t/ha and varied from 0.94 ton/ha (C855) to 4.44 ton/ha (C856). In both sites the seed yields were significantly affected by the hybrid. In terms of the common tested hybrids (C855, C856, C864 and C1008) it was found that the best performed hybrid in Greece was C855 with seed yields 3.87 t/ha, while in Italy was C856 with 4.44 t/ha. The remaining dry biomassyields varied from 0.88 t/ha (2012) to 2.86 t/ha (2011). The gross calorific value (GCV) of the remaining biomass was 4035 kcal/kg and the net calorific value (NCV) was 3852 kcal/kg. The ash content was quite high, varied from 9.21% (Kaiima 93, 2012) to 11.75% (C864, 2012), while the nitrogen content was quite low, ranged from 0.73% (C855) to 0.94% (Kaiima 93).