|Author:||Santos, T. P. dos ; Lopes, C. M. ; Rodrigues, M. L. ; Souza, C. R. de ; Maroco, J. P. ; Pereira, J. S. ; Silva, J. R. ; Chaves, M. M.|
|Book Group Author:||NA|
A study to assess the effects of the partial root zone drying (PRD) irrigation strategy compared with other irrigation systems was carried out in southern Portugal in two field-grown grapevine cultivars, Moscatel and Castelão. We addressed the question of whether by regulating growth and plant water use, the PRD system would enable an equilibrated vegetative development, leading to a favourable capture of solar radiation for photoassimilate production and, at the same time to provide an optimum environment for fruit maturation. Three irrigation schemes were applied in addition to the non-irrigated (NI) vines: partial root drying (PRD), 50% of crop evapotranspiration (ETc), supplied to only one side of the root system while the other one was allowed to dry, alternating sides every 15 days; deficit irrigated (DI), 50% ETc supplied, half to each side of the root system and full irrigated (FI, 100% ETc). During the whole season, FI plants of both cultivars exhibited a high leaf predawn water potential (ψpd, ca. -0.2 MPa) while a progressive decline was observed in NI plants, reaching ψpd values near -0.7 MPa at the end of August. PRD and DI presented intermediate values. PRD vines exhibited a stronger control over vegetative growth compared with DI and FI plants. This was expressed by lower values of total leaf area at harvest, leaf layer number, canopy wideness and water shoot number, allowing a higher light interception at the cluster zone that induced an improvement in some berry quality characteristics. Watering had no significant effects on sugar accumulation in the berries but led to a favourable increase in the must titratable acidity, mainly in Castelão. While in DI and FI treatments, berry skin anthocyanins and phenols content were always lower than in NI, in PRD, there was either no reduction or the reduction was much lower than in the other irrigation treatments. Water use efficiency was increased by ~80% in PRD and DI compared with FI, as a result of almost similar yields in the three treatments. Yield gains of irrigated plants in relation to NI were modest, explained by the rainy spring in both years.
|Pages:||663 - 671|
|Journal:||Functional Plant Biology|
anthocyanins, canopy, crop quality, cultivars,evapotranspiration, fruits, grape must, grapes, growth, interception,irrigation, irrigation systems, leaf area, leaves, maturation, phenols,plant development, root systems, shoots, solar radiation, sugars,titratable acidity, water use, water use efficiency, Portugal, Vitis,Vitis vinifera, Vitidaceae, Rhamnales, dicotyledons, angiosperms,Spermatophyta, plants, eukaryotes, Vitis, Southern Europe, Europe,Mediterranean Region, Developed Countries, European Union Countries,OECD Countries, crown cover, cultivated varieties, leaf canopy,sunlight, Vitaceae, watering, Horticultural Crops (FF003) (New March2000), Plant Breeding and Genetics (FF020), Plant Physiology andBiochemistry (FF060), Plant Water Relations (FF062), Soil WaterManagement (Irrigation and Drainage) (JJ800) (Revised June 2002)[formerly Soil Water Management], Crop Produce (QQ050), Food Compositionand Quality (QQ500)