For all three genotypes, plants und

For all three genotypes, plants under water restriction presented higher (P < 0.05) ChlSPAD values than those under control, during the first 4–6 weeks after the initiation of water restriction (Fig. 1D–F). This significant difference was maintained through the fourth week after water restriction initiation in Sarnav, the fifth in Unica and the sixth in Désirée. The maximum ChlSPAD Amp was recorded two weeks after the initiation of water restriction for Sarnav and Désirée, and one week for Unica. At this latter stage, ChlSPAD Amp values were 3.87, 6.05 and 6.85 SPAD units in Sarnav, Désirée and Unica, respectively. Sarnav, which was the genotype with the lowest DSI showed also the lowest ChlSPAD Amp values (Fig. 2). Senescence in both control and water restriction treatments was reached sooner in Désirée, followed by Unica and finally Sarnav (Table 1).