Water deficit effects on canopy light interception, chlorophyll fluorescence, and stomatal conductance in Moroccan alfalfa genotypes

Water deficit is the major constraints causing negative effects on forage crops in many regions worldwide especially North Africa. This constraint will aggravate because of climate change in the future. The present study aims to assess several physiological and biochemical parameters in three alfalfa varieties subjected to severe water deficit. Plants were irrigated with 100% ETc (crop evapotranspiration) water amount as well-watered and 50% ETc as water deficit. The results showed that water deficit significantly reduced dry matter (DM), photosynthetically active radiation (PAR(i)), light conversion (eb) and electron transport rate in all the studied genotypes. Adis variety had the lowest DM reduction of 22.7% under water stress. Moapa (MO) showed a reduction of 51.5%. The lowest eb value of 1.57 kg/mu mol m(-2) d(-1) was observed for MO under water stress. Overall, next to biomass and water uptake, the photosynthetic parameters may constitute additional reliable criteria for the selection of water deficit tolerant variety of alfalfa to support the breeding program by INRA for the Mediterranean well adapted alfalfa varieties.