Effects of interspecific grafting between Capsicum species on scion fruit quality characteristics

Authors: VEGA ALFARO, ANDREY - University Of Wisconsin; Bethke, Paul; NIENHUIS, JAMES - University Of Wisconsin

Submitted to: HortScience
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/2/2021
Publication Date: 9/27/2021
Citation: Vega Alfaro, A., Bethke, P.C., Nienhuis, J. 2021. Effects of interspecific grafting between Capsicum species on scion fruit quality characteristics. HortScience. 56(11):1347-1353. https://doi.org/10.21273/HORTSCI15948-21.
DOI: https://doi.org/10.21273/HORTSCI15948-21

Interpretive Summary: Sweet peppers are widely grown, but are susceptible to various diseases found in soils. Several kinds of hot peppers are grown commercially, and some of these contain valuable disease resistance and agronomic traits. We evaluated the effects of grafting sweet peppers as scions onto hot pepper rootstocks. Specific combinations of rootstock and scion resulted in earlier flowering time and increased fruit size, which may be advantageous to pepper growers. Pepper fruit retained the shape of sweet rather than hot peppers and did not produce compounds that cause fruit to be hot. These findings suggest that interspecific grafting may be a valuable method for combining resistance to soil borne diseases and improved root function with sweet pepper production.

Technical Abstract: Production of peppers, (Capsicum annuum L) is often limited, especially in tropical environments, by susceptibility to soil pathogens such as Ralstonia solanacearum. Grafting onto selected rootstocks can increase adaptation to abiotic stress and is an alternative to pesticides for mitigating effects of soil borne pathogens. Cultivars of two species of peppers, C. baccatum and C. Chinenese, are tolerant or resistant to an array of soil borne pathogens and have potential as rootstocks; nevertheless, knowledge of how interspecific grafting may affect scion fruit quality is unknown. Flowering time, yield and fruit characteristics were evaluated over two years for C. annuum L. (sweet pepper) cultivars, ‘Dulcitico’, ‘Nathalie’ (in one year), ‘Gypsy (in one year) and ‘California Wonder’ grafted onto ‘Aji Rico’ (C. baccatum) and ‘Primero Red’ (C. chinense) rootstocks, as well as self-grafted and non-grafted scion checks. In 2020, the rootstocks per se were evaluated. The four rootstock combinations and three scions were field evaluated in a factorial randomized complete block design at the West Madison and Eagle Heights Agricultural Research Stations (ARS) located in Madison, WI in 2017 and 2020, respectively. Differences among the scion fruit quality characteristics were consistent with cultivar descriptions. No scion x rootstock interactions were observed. Rootstocks did not result in changes in total fruit number, yield, fruit length to width ratio or soluble solids of scions compared to self- and non-grafted checks. Rootstock ‘Primero Red’ did increase fruit weight and decreased days to flowering regardless of scion compared to self-and non-grafted checks. All scions were sweet (non-pungent) cultivars and both ‘Primero Red’ and ‘Aji Rico’ rootstocks are pungent. No capsaisionoids were detected in the fruit of sweet pepper scions grafted onto pungent rootstocks. The results indicate interspecific grafts involving ‘Aji Rico’ and ‘and ‘Primero red’ will not have deleterious effects on fruit characteristics of sweet pepper, C. annuum, scions.