Water use and water-use efficiency of Isabgol (Plantago ovata) and French psyllium (Plantago psyllium) in different irrigation regimes.

Water supply is a major constraint to crop production in Mediterranean climate. This study examined water use, water-use efficiency, mucilage and seed yield of Isabgol (Plantago ovata) and French psyllium (Plantago psyllium) from 2 experiments over 2005 to 2006. In this study, Isabgol and French psyllium which are used as an anti-diabetic plant were exposed to three different irrigation regimes and three different plant densities. Combined analysis results showed that year effect was significant in all traits. Limited irrigation regimes significantly decreased seed yield, biological yield and water use in compared to control although, WUEs and mucilage percentage in both species significantly increased. The highest biological yield belongs to control and R2 (Irrigation terminated at the start of flowering with a complementary irrigation at the seed formation stage) in medium density and the highest mucilage percentage were observed in R3 (irrigation terminated at the start of flowering) and low density in both species. Totally, seed yield, biological yield and mucilage percentage were higher in Isabgol compare with French psyllium. Contrary to WUEb, WUEs in Isabgol was more than French psyllium. Our results showed that there is a high potential for saving water through medium stress (R2) using locally adapted plants in the semi-arid conditions of Karaj. These crops can serve as alternative sources of income in dry years.