Physiological response of red pepper to different irrigation regimes under drip irrigation in the Mediterranean region of Turkey

A study was conducted to analyse the physiological response of red pepper (Capsicum annuum L.) to different irrigation regimes by means of periodical measurements of leaf water potential (LWP) and stomatal resistance (rs) and crop water stress index (CWSI) at midday during 2010 and 2011 seasons in the Mediterranean region of Turkey. The treatments consisted of full irrigation (FI), deficit irrigation (DI-75, DI-50), partial root zone drying (PRD-A, PRD-F, A: alternative, F: fixed). The greatest yield was obtained from the FI treatment followed by DI 75, PRD-A, DI-50 and PRD-F treatments resulted in the smallest yield. The FI irrigation treatment had less stomatal resistance (17.4 s cm(-1) in 2010 and 16.4 s cm(-1) in 2011) and CWSI (0.25 in 2010 and 0.27 in 2011) in comparison with deficit irrigation treatments. Red pepper performed best at FI with a corresponding leaf water potential of -0.65 to -0.53 MPa for experimental years. There were large differences among treatments in LWP, CWSI and rs, indicating that crop responded differently to different soil water levels. Significant relationship between stomatal resistance, water use and yield were obtained. The results also revealed significant dependency among CWSI, rs and LWP were found.