*3.3. Yield and Water-Use E*ffi*ciency*

The effects of rootstock type and irrigation technique on tomato yield traits and WUE in the first experiment are presented in Table 4, Average fruit weight, fruit number per plant and total yield were affected by rootstock and were higher in grafted plants than in self-grafted ones. Early yield was significantly affected by irrigation technique and highest values were noted for DI plants differing only with plants cultivated under PRD regime. WUE was affected by rootstock and irrigation. As expected, plants under DI and PRD had almost double values of WUE. Emperador and Maxifort plants significantly differed from self-grafted ones and on average had 40% higher WUE values.

**Table 4.** Yield parameters and water-use efficiency of grafted tomato plants grown with one stem under three irrigation techniques in the first year of the experiment.


\* Significant differences between treatments (LSD test at *p* ≤ 0.05) are indicated with different letters within columns. ns—non-significant.

Yield parameters and WUE results for second year are shown in Table 5. As in the first year, plants grafted on commercial rootstocks had significantly (*p* ≤ 0.001) higher fruit mean weight and also number of fruits per stem. Early yield was affected (*p* ≤ 0.001) by plant type and highest was noted for self-grafted Attiya grow with one stem. Yield WUE was significantly (*p* ≤ 0.001) higher for Emperador and Maxifort grafted plants and also for plants grown under both types of reduced irrigation (DI + PRD).

Total yield results for second year are shown in Figure 2. Although, the interaction between factors was not significant, it was important to compare yield of same plant type under different irrigation. This analysis showed that grafted plants with commercial rootstocks grown under FI had highest total yield that differed from same plants type grown under PRD, but not significantly different from DI. In addition, one stem self-grafted plants from all irrigation regimes did not differed to each other and two stem ones had lowest yield had under PRD.


**Table 5.** Yield parameters and water-use efficiency of grafted tomato plants grown with one and two stems under three irrigation techniques in the second year of the experiment.

\* Significant differences between treatments (LSD test at *p* ≤ 0.05) are indicated with different letters within columns. ns—non-significant.

**Figure 2.** Total yield (kg stem<sup>−</sup>1) of grafted tomato plants grown with one or two stems under three irrigation techniques. Vertical bars represent SE values (*n* = 4). Different letters above column indicate a significant difference by the LSD test at *p* < 0.05. ATT—one-stem Attiya; AT—two-stem Attiya; EM—Emperador; MX—Maxifort.
