Effect of Inter and Intra Row Spacing on Some Agronomic Traits of Red Castor (Ricinus communis L.)

Determination of planting spacing for castor (Ricinus communis L.) is very important for obtaining optimum seed yield. This experiment was conducted to study the effects of inter and intra row spacings on some agronomic traits of red castor using split-plot arrangments in randomized complete block design with four replications in 2006 at the Kabotarabad Agriculture Research Station of Isfahan. Main plots were three inter row spacings (55, 75 and 95 cm) and sub-plots were three intra row spacings (20, 30 and 40 cm). Results showed that with increasing inter row spacing, physiological maturity was enhanced. Inter row and intra row spacings had significant effect on plant height, stem diameter and plant dry matter. By increasing plant density, plant height and plant dry matter increased and stem diameter decreased. Inter row spacing significantly affected on number of candles plant-1, number of candles m-2, candle length, 1000 seed weight, seed yield and harvest index. Inter row spacing had no significant effect on number of seed candle-1. Intra row spacing had no significant effect on number of seed candle-1 and 1000 seed weight. By increasing plant density, seed yield increased. Seed yield variation had similar trend to number of candles m-2, candle length, number of seed candle-1 and harvest index. However, variation in trend of seed yield was reversed to the number of candle plant-1 and 1000 seed weight. The highest seed yield (1423 Kg ha-1) was obtained in 55 cm inter row and 20 cm intra row spacings (91 thousand plant ha-1).