Grafting Affects Tomato Growth, Productivity, and Water Use Efficiency under Different Water Regimes

The effects of grafting two greenhouse tomato cultivars (Durinta and Valouro F1) onto three tomato rootstocks (Beaufort, Maxifort, and Spirit) under different irrigation regimes [(50%, 75%, and 100% crop EvapoTranspiration (ETc)] were studied by evaluating the vegetative growth, proline, chlorophyll, and mineral content of the leaves as well as fruit yield and Total Yield Water Use Efficiency (TYWUE). Plant height, stem diameter, leaf area, and total yield decreased, whereas proline and TYWUE increased, with increasing water stress. Between the two tested cultivars, Durinta showed more vigorous growth than Valouro. Plant growth, proline, Ca+2 and K+ concentrations, fruit yield, and TYWUE were higher in grafted plants than in non-grafted plants. Adverse effect of high water stress (50% ETc) was evident in the non-grafted plants, particularly in Valouro. A positive effect of grafting was observed when Beaufort was used as the rootstock. Durinta grafted onto Beaufort (DB) under moderate irrigation regime (75% ETc) exhibited water savings (25%) and higher yield (21.6–30.8%) and TYWUE (55.1–55.5%) than fully irrigated (100% ETc) control (non-grafted Durinta). The results indicated that grafting onto appropriate rootstock could alleviate some of the negative effects of water limitation on greenhouse tomato plants.