Castor (Ricinus communis), is an important industrial crop with 45-55% oil and a unique fatty acid, ricinoleic acid (80-93% of oil). Castor oil and its derivatives are used in the manufacture of several industrial products like lubricants, medicine, laxatives, nail polishes, paintings etc. India accounts for 69% of the world’s castor area and 85% of the production with a highest productivity of 1.8 t/ha (2016-17). Commercial exploitation of heterosis in castor led to a rise in productivity from <0.3 tha to 1.8t ha1 during the last five decades in India. More than 90 percent castor growing area, especially under irrigated conditions is occupied by castor hybrids.
Castor is monospecific and belongs to family Euphorbiaceae (2n=20). Castor is a highly cross- pollinated crop by wind and insects to some extent as pollinating agents. Seed production in castor is challenging due to environmentally sensitive sex expression in parental lines. Success of seed production depends on good seed source, isolation distance and roguing.
Basic Sex expression forms in castor: Monoecious: a spike with basal 1/3rd to half portion filled with male flowers and the upper portion female flowers; Pistillate: a spike with female flowers completely; Interspersed Staminate flowers (ISF): Staminate (male) flowers interspersed throughout the spike; Revertant: A pistillate spike that reverts to monoecious in later orders 89°F Mostly sunny Pistillate ISF Monoecious High male Sex expression in castor is highly influenced by environmental conditions. Winter season, <30°C monthly mean temperatures, young age of plants, high nutrition especially nitrogen promote female flowers in different spike orders. Where as summer season, >32°C monthly mean temperature, old age or late order spikes, low nutrition or nitrogen promote male flowers in different spike orders
Morphological characters: Castor has wide variation morphological characters like stem color, bloom and capsule spines, Plant type (Normal /dwarf), Branching (Divergent/ convergent), Shape of spikes (Conical, cylindrical, umbrella) etc.
Seed Production of varieties or male lines:
Spacing: 90×45 cm or 90×60 cm; Seed rate: 2-3 kg/ acre
First stage (Before flower initiation < 30-45 days after sowing): Remove the morphological deviants
Second stage (During flowering stage l.e. 45-65 DAS): Flowering of spike extends over a period of 10 to 15 days.
Original Link: https://icar-iior.org.in/