*3.4. Intrinsic and Extrinsic Fruit Quality*

Hue color parameter in fruits from plants grafted onto *S.torvum* and *S. aethiopicum* gr. *gilo* (accession 1) had the highest values (360.3 and 360.2, respectively) (Table 3).


**Table 3.** Rootstock effects on Hue◦, fruit dry matter, firmness, and soluble solids content (SSC) in 'Scarlatti' F1 scion.

Values within a column and a year followed by the same letter are not significantly different at *p* ≤ 0.05 (Tukey HSD Test). The significance is designated by asterisks as follows: \*, statistically significant differences at *p*-value below 0.05; \*\*, statistically significant differences at p-value below 0.01; \*\*\*, statistically significant differences at *p*-value below 0.001; NS = not significant.

Treatments tested had no effects on fruit dry matter and firmness (Table 3).

Rootstock significantly influenced SSC (Table 3). The highest value of SSC (4.6, 4.9 and 4.6 ◦Brix, respectively) were found in plants grafted onto *S. aethiopicum* gr. *gilo* (accessions 1 and 2) and *S.* *melongena* × *S. aethiopicum* gr. *gilo* hybrid, whereas the lowest value (3.9 and 4.1 ◦Brix, respectively) were observed in plants grafted onto *S. torvum* and 'Scarlatti'(Table 3).

'Scarlatti' scions grafted onto *S. aethiopicum* gr. *gilo* (accession 1) and *S. melongena* × *S. aethiopicum* gr. *gilo*, had the highest values of L0 central area (Table 4), while fruits from plants grafted onto *S. aethiopicum* gr. *gilo* (accession 2) rootstocks had the lowest value.

**Table 4.** Rootstock effect on pulp lightness measured immediately after cutting (L0) in the central and lateral area and the fruit browning (ΔL30) of the lateral area in 'Scarlatti' F1 scion.


Values within a column and a year followed by the same letter are not significantly different at *p* ≤ 0.05 (Tukey HSD Test). The significance is designated by asterisks as follows: \*, statistically significant differences at p-value below 0.05; \*\*, statistically significant differences at *p*-value below 0.01; \*\*\*, statistically significant differences at *p*-value below 0.001; NS = not significant.

Data collected for L0 lateral area supported the trend established for L0 central area (Table 4).

*S. aethiopicum* gr. *gilo* (accessions 1 and 2) and *S. melongena* × *S. aethiopicum* gr. *gilo* hybrid rootstocks induced the highest ΔL30 lateral area values (Table 4). While, *S. torvum* rootstock induced the lowest one.

ANOVA for total anthocyanins was not statistically significant (Table 5).

**Table 5.** Rootstock effect on total antocyanins, glycoalkaloids, chlorogenic acid, and proteins in 'Scarlatti' F1 scion.


Values within a column and a year followed by the same letter are not significantly different at *p* ≤ 0.05 (Tukey HSD Test). The significance is designated by asterisks as follows: \*, statistically significant differences at *p*-value below 0.05; \*\*, statistically significant differences at *p*-value below 0.01; \*\*\*, statistically significant differences at *p*-value below 0.001; NS = not significant; fw = fresh weight.

The highest glycoalkaloids content was observed in fruits from ungrafted plants and in those from plants grafted onto *S. melongena* × *S. aethiopicum* gr. *gilo* rootstocks (Table 5).

Fruits from 'Scarlatti' grafted on *S. torvum*, *S. aethiopicum* gr. *gilo* (accession 1), and 'Scarlatti' self-grafted plants had the highest chlorogenic acid content, whereas, fruits from plants grafted onto *S. melongena* × *S. aethiopicum* gr. *gilo* hybrid rootstock showed the lowest value (Table 5).

We found that protein content in fruits from plants grafted onto *S. aethiopicum* gr. *gilo* (accession 1) was slightly higher than those from 'Scarlatti' ungrafted, self-grafted, and *S. torvum* grafted plants. The lowest protein content was detected in fruits from plants grafted onto *S. aethiopicum* gr. *gilo* (accession 2) (Table 5).

Rootstock significantly affected mineral content (Figure 1).

Ungrafted, self-grafted, and *S. torvum* rootstock grafted plants had the highest fruit P content (538, 551, and 541 mg·100 g−<sup>1</sup> of dw, respectively). The lowest fruit P content value (395.4 mg·100 g−<sup>1</sup> of dw) was found in *S.melongena* × *S. aethiopicum* gr. *gilo* hybrid rootstock (Figure 1). Fruits harvested from plants grafted on *S. aethiopicum* gr. *gilo* (accession 1) rootstock had a significantly lower K content (302.9 mg·100 g−<sup>1</sup> of dw) in comparison to those grafted onto 'Scarlatti', *S. torvum*, *S. melongena* <sup>×</sup> *S. aethiopicum* gr. *gilo* hybrid, *S. aethiopicum* gr. *gilo* (accession 2), and 'Scarlatti ungrafted (341.0, 349.0, 341.3, 359.1, and 354.4 mg·100 g−<sup>1</sup> of dw, respectively) (Figure 1). Moreover, no significant differences were found among plants grafted onto 'Scarlatti', *S. torvum*, *S. melongena* × *S. aethiopicum* gr. *gilo* hybrid, *S. aethiopicum* gr. *gilo* (accession 2), and 'Scarlatti ungrafted for fruit K content. 'Scarlatti' grafted onto *S. melongena* <sup>×</sup> *S. aethiopicum* gr. *gilo* hybrid gave the highest fruit Ca content (108.9 mg·100 g−<sup>1</sup> of dw), whereas fruits from plants grafted *S. aethiopicum* gr. *gilo* (accession 2) gave the lowest Ca fruit content (99.4 mg·100 g−<sup>1</sup> of dw) (Figure 1). 'Scarlatti' grafted onto *S. aethiopicum* gr. *gilo* (accessions 1 and 2) and *S. melongena* × *S. aethiopicum* gr. *gilo* hybrid had the highest Mg content (19.3, 18.1, and 18.6 mg 100 g−<sup>1</sup> of dw, respectively) (Figure 1), whereas the lowest Mg contents were found in fruits from 'Scarlatti' grafted on *S. torvum* (13.8 mg·100 g−<sup>1</sup> of dw).
