Vegetable Grafting: The Implications of a Growing Agronomic Imperative for Vegetable Fruit Quality and Nutritive Value

Abstract

Grafting has become an imperative for intensive vegetable production since chlorofluorocarbon-based soil fumigants were banned from use on grounds of environmental protection. Compelled by this development, research into rootstock–scion interaction has broadened the potential applications of grafting in the vegetable industry beyond aspects of soil phytopathology. Grafting has been increasingly tapped for cultivation under adverse environs posing abiotic and biotic stresses to vegetable crops, thus enabling expansion of commercial production onto otherwise under-exploited land. Vigorous rootstocks have been employed not only in the open field but also under protected cultivation where increase in productivity improves distribution of infrastructural and energy costs. Applications of grafting have expanded mainly in two families: the Cucurbitaceae and the Solanaceae, both of which comprise major vegetable crops. As the main drives behind the expansion of vegetable grafting have been the resistance to soilborne pathogens, tolerance to abiotic stresses and increase in yields, rootstock selection and breeding have accordingly conformed to the prevailing demand for improving productivity, arguably at the expense of fruit quality. It is, however, compelling to assess the qualitative implications of this growing agronomic practice for human nutrition. Problems of impaired vegetable fruit quality have not infrequently been associated with the practice of grafting. Accordingly, the aim of the current review is to reassess how the practice of grafting and the prevalence of particular types of commercial rootstocks influence vegetable fruit quality and, partly, storability. Physical, sensorial and bioactive aspects of quality are examined with respect to grafting for watermelon, melon, cucumber, tomato, eggplant, and pepper. The physiological mechanisms at play which mediate rootstock effects on scion performance are discussed in interpreting the implications of grafting for the configuration of vegetable fruit physicochemical quality and nutritive value.

The effectiveness of growth cycles on improving fruit quality for grafted watermelon combinations

“…Fruit size is the most prominent change following grafting of watermelon onto rootstocks. Contrarily to the fruit size, the fruit shape index defined by the ratio of equatorial and longitudinal lengths was unaffected or minimal by grafting combinations on watermelon grown under low tunnel and in open field conditions (Davis & Perkins-Veazie, 2005;Alan et al, 2007;Rouphael et al, 2010;Kyriacou et al, 2017). Dur findings of an increase in the fruit shape index agree with a later report of Turhan et al (2012).…”

“…Besides disease resistance and tolerance to low/high soil temperatures, watermelon rootstocks, especially those of C. maxima × C. moschata hybrids can enhance plant vigor, growth, and yield since they are much more vigorous than the bottle gourd rootstock (Alan et al, 2007;King et al, 2010); however, reports on fruit quality such as rind thickness, color, fruit firmness, total soluble solids, and sugar are rather conflicting being increasing, decreasing or remaining unaffected (Miguel et al, 2004;Davis et al, 2008a;Rouphael et al, 2010;Fallik & Ilic, 2014;Kyriacou et al, 2017).…”

Plant- and Seaweed-Based Extracts Increase Yield but Differentially Modulate Nutritional Quality of Greenhouse Spinach through Biostimulant Action

“…However, the SPAD index values, widely used as a non-invasive and non-destructive estimate of chlorophyll content were highly influenced biostimulant treatments ( Table 2). These findings have been observed in a wide range of horticultural crops including tomato, spinach, lettuce, melon treated with biostimulants of different origin including amino acids, protein hydrolysate as well as plant and seaweed extracts [7,13,18,26,[38][39][40][41]. The higher SPAD index values observed in spinach plants treated with biostimulants (PH, SWE or VO + SWE) could be also considered a mechanism by which biostimulant application can promote N uptake efficiency.…”

“…Among the physical properties of vegetable species that significantly influence consumer preference is the colorimetric CIELAB components in particular brightness (L*), redness (a*) and yellowness (b*) [39]. In the current study, neither the application with legume-derived PH nor biostimulant treatment with E. maxima or vegetable oils, herbal extracts in addition to A. nodosum had a significant effect on L* (average 42.2), a* (average −15.2), or b* (average 21.5) parameters (Table 2).…”

Arsenic Accumulation in Grafted Melon Plants: Role of Rootstock in Modulating Root-To-Shoot Translocation and Physiological Response

“…In horticultural systems, vegetable grafting is a multipurpose technique improving crops performances and product quality under both optimal and suboptimal growth conditions [15][16][17]. It has been proposed as a means to reduce the heavy metals uptake and translocation to the shoots and the edible parts [18,19], although the mechanisms underlying such impediment are still unclear [20].…”