Early water stress effects on pollen viability, berry set and embryo development in cv. 'Syrah' (Vitis vinifera L.)

Early water deficit at bloom results in poor berry set and/or a grape yield reduction. The purpose of this work was to determine the effects of early water stress in a berry's development. The experiment was carried out in a SupAgro ECOTRON System in Montpellier, France. Seven year- old 'Syrah' vines were used. The pot's surface was protected from rainfall, and the growing medium was perlite+coarse sand with controlled drainage. The treatments were WS0 (control): 41/day, WS1.: 3 l/day, WS2 : 2 l/day, and WS3 : 1 l/day. 'Ihe water deficit was carried out from the 17th to the 27th Eichhorn-Lorenz (E-L) stages. In order to emphasise details of the embryo development, a paraffin section method and technique was used. With the early water stress, there was no effect on the pollen viability and pollen germination ratios. The berry set ratio was reduced and the berry development were affected negatively by the early water stress. Between the 19th and the 27th E-L stages, an early water stress in 'Syrah' was noted, with decreases in the pre-dawn leaf water potential values below -0.8 MPa. The water deficit affected the berry growth and the development negatively.