Guar seed prices on Tuesday rose by Rs 2 to Rs 3,874 per 10 quintal in futures trade after speculators increased their positions driven by a firm trend in spot market. On the National Commodity and Derivatives Exchange, guar seed for January contracts increased by Rs 2, or 0.07 per cent, to Rs 3,874 per 10 quintal with an open interest of 13,485 lots. However, guar seed for February delivery traded flat at Rs 3,920 per 10 quintal with an open interest of 49,960 lots. According to marketmen, raising of bets by speculators tracking a firm trend in spot market on thin supplies from growing belts mainly led to the rise in guar seed prices here.