Ecology, Environment and Conservation Paper

RADIATION IMPACT AND BIOLOGICAL VARIATION OF CASTOR BEAN IN EGYPT AS A BIOFUEL CROP

Ezzat A. Kotb and Ahmed M. Algharib

Abstract

Seeds of four castor bean landraces were obtained from different locations in Egypt. The seeds were investigated first for their physical properties and latter planted in the research farm of the soils and water Department, Nuclear Research Centre, Atomic Energy Authority, Egypt. The morphoagronomic properties and oil parameters were studied. After harvest, seeds of the four landraces were irradiated at 0, 100, 200, 300, 400, 500, 600, 700 and 800 Gy in gamma cell and fatty acid composition were studied. Based on seed size and color, four main landraces of dry dehiscent castor seed types were observed: gray small-seeded landrace (GSSL) (L1), brown medium-seeded landrace (BMSL) (L2), reddish medium-seeded landrace (RMSL) (L3) and brown large-seeded landrace (BLSL) (L4). The seed characters ranged from 0.18 - 0.71 g weight, 0.86 - 2.16 cm height, 0.46 - 1.30 cm width, and 0.11 - 0.57cm thickness. The red medium-seeded landrace resulted plants with greater height (320cm). The brown medium-seeded landrace recorded the tallest main spike (38.0cm), highest number of capsules spike-1 (39), maximum number of capsules plant-1 (743.7), highest seed yield plant-1 (1.10kg), highest seed yield ha-1 (1.75ton), and maximum oil yield ha-1 (648.1 kg). The gray small-seeded landrace produced seeds with the highest oil percentage (44.01%). The brown large-seeded landrace produced the heavier grains (68.06g). Five fatty acids were found in castor bean oil (palmitic, stearic, oleic, linoleic, and ricinoleic acid). A slight variation was noted in ricinoleic acid, which was the major component of castor oil ranging from 81.96 to 86.80%. The brown medium-seeded landrace that exhibited a high seed yield, oil content, and proper fatty acid composition will be further investigated for biodiesel production. The results also showed that the increase of radiation dose led to an increased proportion of saturated acids and decreased the contents of unsaturated acids.