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The present experiment addressed the effects of two phosphorus regimes (30 and 90 kg ha−1, hereafter P30 and P90) on yield and composition of eggplant fruits in 'Birgah' and 'Dalia', whether or not these cultivars were grafted onto Solanum torvum 'Espina'. The P30 regime did not reduce yield, and promoted fruits' dry matter and total phenols content, along with their concentrations of macronutrients, mesonutrients (S and Na) and micronutrients (mostly Cu, B, Zn); however, their Fe concentrations were depressed. The rootstock 'Espina' increased fruit yield, dry matter content, epicarp chroma (in 'Birgah') and Ca content, together with their concentrations of B and Zn (especially at P30), but reduced their Fe content, mostly under P30. Thus, the reduced P supply and grafting proved to be effective tools to enhance fruit yield, carpometric and almost all nutritional traits in eggplant, in a framework of more sustainable crop management. However, the reduced fruit concentration of Fe suggests that the affinity of the rootstock with specific micro minerals should be taken into account, along with the option to adopt complementary practices (e.g., targeted micronutrient fertilizations) to manage the micro mineral composition of eggplants. [ABSTRACT FROM AUTHOR]

• Grafting has potential to improve chill tolerance in vegetable crops. • We studied Capsicum baccatum (CB) and C. pubescens (CP) accessions as rootstocks for pepper. • CB 9 and CP 3 were more vigorous than the commercial rootstock 'Capsifort' under chilling stress. • When grafted onto CB 9 and CP 3 the scion 'Tiberio' showed a higher chill tolerance. • We selected suitable rootstock germplasm to improve chill tolerance of grafted pepper. This study evaluated the effectiveness of rootstocks germplasm to enhance the chilling tolerance of Capsicum annum L. We compared 2 accessions of C. baccatum , i.e., CB 5 and CB 9, and 3 accessions of C. pubescens , i.e., CP 2, CP 3, and CP 4, together with commercial controls across 3 experiments. Experiment 1 (Exp 1) aimed to evaluate these genotypes adaptation compared to rootstock cv. 'Capsifort' to chilling temperatures and was performed in growth chambers for 28 days under two thermal regimes, i.e. optimal (25–15 °C for 12 h/day) and suboptimal (15–5 °C for 12 h/day). In Exp 2 the scion cv. Tiberio was grafted onto these rootstocks and grown under suboptimal temperature for 28 days in comparison to ungrafted control. Exp 3 evaluated the same graft combinations in a commercial greenhouse, to assess the effects of grafting on fruit yield and quality of the scion 'Tiberio' compared to ungrafted and self-grafted controls. In Exp 1, CP 3 showed the best photosynthetic performances, whereas CP 2 and CP 3 outperformed 'Capsifort' for plant biomass under suboptimal temperature. In Exp 2, chlorophyll fluorescence was higher in the combination 'Tiberio'/CB 9 than in 'Tiberio', while 'Tiberio'/CP 3 had a higher photosynthetic rate. The stomatal conductance was higher in 'Tiberio'/CP 3 and 'Tiberio'/CP 4 than in 'Tiberio'. All the graft combinations reduced the leaf proline content compared to the ungrafted plants. In Exp 3 the graft combinations 'Tiberio'/'Capsifort', 'Tiberio'/CB 5, 'Tiberio'/CB 9 and 'Tiberio'/CP 3 produced the highest marketable yields, but 'Tiberio'/'Capsifort', 'Tiberio'/CB 5, and 'Tiberio'/CB 9 had the highest number of discarded fruits per plant. 'Tiberio'/CP 2 fruits had lower titratable acidity values than 'Tiberio', whereas 'Tiberio'/CB 9 had the highest antioxidant activity. Overall, our results showed that CB 9 and CP 3 consistently proved positive performance on 'Tiberio', while CP 2 performed well under low temperature conditions only. [ABSTRACT FROM AUTHOR]

Grafting is a valuable tool for managing problems of tomato soil-borne pathogens and pests, but often generates unpredictable effects on crop yield and product quality. To observe these rootstocks-induced changes, experimental designs including many rootstock-scion combinations are required. To this end, a greenhouse experiment was conducted on 63 graft combinations, involving seven cherry tomato scions grouped in large, medium and small-fruited, and eight rootstocks with different genetic backgrounds (crosses between Solanum lycopersicum and S. habrochaites or S. peruvianum or S. pimpinellifolium, plus an intraspecific hybrid), using ungrafted controls. The response of the graft partners was firstly analyzed individually using the environmental variance (σ2E), then by grouping them by classes. When analyzed individually, the scion genotype influenced fruit L*, b*, shape index, total soluble solids (TSS) and its ratio with tritatable acidity (TSS/TA), whereas plant growth and yield were unpredictable. After clustering the graft partners, some of these responses were attributable to the imposed classes. The S. habrochaites-derived hybrids maximized plant biomass, unlike the S. pimpinellifolium ones. Both classes reduced fruit biomass in small- and medium-fruited scions (by 11 and 14%, respectively). The S. habrochaites and S. peruvianum hybrids reduced a* and TSS, whereas promoted TA. L-ascorbic acid was reduced by grafting (from −23 to −45%), in the S. pimpinellifolium group too, indicating, even in low vigor rootstocks, a dilution effect worsening this nutraceutical trait of tomatoes. [ABSTRACT FROM AUTHOR]

The present experiment addressed the effects of two harvest stages, namely breaker (S1) and turning (S2), on compositional and sensory profile of grafted, greenhouse elongated tomatoes cv. "Sir Elyan". The rootstocks "He-Man", "Interpro", and "Armstrong" were used. The S1 fruits showed a higher dry matter content, firmness and titratable acidity when compared to the S2 ones (by 6%, 3%, and 15%, respectively). They showed, also, the highest L-ascorbic acid concentration and antioxidant activity. Differently, soluble solid content, lycopene and β-carotene increased in the S2 fruits (by 4%, 92%, and 26%, respectively). Excepting methyl salicylate, all the volatiles detected peaked in the S2 fruits, which were scored by panelists as sweeter and more flavorful than the S1 ones. Among the rootstock genotypes, "He-Man" promoted fruits firmness, carotenoids concentration and antioxidant activity, irrespective of the harvest stage. "Interpro" enhanced the sensory attributes of the S1 fruits in terms of bitterness, sourness, sweetness and flavor. Differently, sweetness, sourness, and tomato flavor of the S2 fruits were promoted by "Armstrong". The results highlight the influence of rootstock genotype on the nutraceutical and sensorial profile of "Sir Elyan" fruits harvested at early ripening stages. [ABSTRACT FROM AUTHOR]

A greenhouse experiment was conducted to study the effects of the O2 root zone level and grafting on chlorophyll fluorescence, photosynthesis and growth of cherry tomato grown in a hydroponic system. Two O2 concentrations in the root zone, namely Ox (saturation level) and Ox- (2–3 mg L−1), were applied for 30 days on self-grafted cherry tomato Dreamer or grafted onto the hybrids Arnold, Beaufort, Maxifort and Top Pittam. Root hypoxia increased minimum fluorescence (by 10%) while it decreased variable fluorescence and the maximum quantum yield of PSII (up to 16 and 8%, respectively). Moreover, it reduced leaf photosynthesis, transpiration and stomatal conductance (by 12, 17 and 13%, respectively), whereas it increased leaf electrolyte leakage (by 2.1%). The graft combinations showed a different ability in buffering the effects of root hypoxia on plant growth and related components, and these differences were related to their root biomass. The minimum fluorescence was negatively correlated to plant growth, so it may be a useful indicator to select tolerant rootstocks to root hypoxia. Our results suggest the occurrence of both diffusive and metabolic constraints to tomato photosynthesis under root hypoxia, a condition that can be mitigated by selecting rootstocks with a more developed root system. [ABSTRACT FROM AUTHOR]

The bio-agronomical response, along with the arsenic (As) translocation and partitioning were investigated in self-grafted melon "Proteo", or grafted onto three interspecific ("RS841", "Shintoza", and "Strong Tosa") and two intraspecific hybrids ("Dinero" and "Magnus"). Plants were grown in a soilless system and exposed to two As concentrations in the nutrient solution (0.002 and 3.80 mg L−1, referred to as As− and As+) for 30 days. The As+ treatment lowered the aboveground dry biomass (−8%, on average), but the grafting combinations differed in terms of photosynthetic response. As regards the metalloid absorption, the rootstocks revealed a different tendency to uptake As into the root, where its concentration varied from 1633.57 to 369.10 mg kg−1 DW in "Magnus" and "RS841", respectively. The high bioaccumulation factors in root (ranging from 97.13 to 429.89) and the low translocation factors in shoot (from 0.015 to 0.071) and pulp (from 0.002 to 0.008) under As+, showed a high As mobility in the substrate–plant system, and a lower mobility inside the plants. This tendency was higher in the intraspecific rootstocks. Nonetheless, the interspecific "RS841" proved to be the best rootstock in maximizing yield and minimizing, at the same time, the As concentration into the fruit. [ABSTRACT FROM AUTHOR]