LAUSR

As chia (Salvia hispanica L.) is spreading in new environments, information on its photosynthetic and agronomic behavior is scarce. This research is focused on the physiological characteristics (photosynthetic rate, conductance to H2O, transpiration rate, intercellular CO2 concentration) of chia with different water supply and from two sources: a commercial Black chia (P) and a long-day flowering mutant (G8). Irrigation treatments were: full (V100) with soil water restitution up to field capacity, half (V50) where half of the water of V100 was given, and no irrigation (VO). Water shortage reduced the photosynthetic rate by 25% between V100 and V0; transpiration was reduced significantly only in the P genotype between V100 and V0 by 52%. Leaf water potentials ranged between − 1.1 (V100) and − 2.0 (V0). Leaf area and total dry matter decreased significantly in response to water shortage due to reduced photosynthetic activity and lower water availability. The G8 genotype showed higher photosynthetic rate, but lower leaf water potential and overall biomass accumulation and leaf area than the P genotype. According to our results Water Use Efficiency increased with water availability and was higher in the P genotype at all irrigation levels, ranging from 0.5 g l−1 in G8 V0 to 1.5 g l−1 in P V100.