Bell pepper rootstocks with multiple resistance to soilborne diseases

Abstract

Bell pepper rootstocks with multiple resistance to soilborne diseasesGrafting has been increasingly used to overcome soilborne pathogens. The commercial rootstock hybrids AF-8253 (Sakata) and Fortaleza (Takii), as well as Embrapa's new hybrid, BRS Acará, were evaluated as rootstocks for the bell pepper hybrids Margarita (Syngenta) and Pampa (Clause) as scions, under natural infestation of Ralstonia pseudosolanacearum, as well as upon artificial inoculation with a) ten Ralstonia isolates, b) one Phytophthora capsici isolate, c) Meloidogyne incognita race 1, and d) Meloidogyne enterolobii (only rootstocks for c and d). Grafted bell peppers consistently showcased a higher productivity than did non-grafted ones under natural R. pseudosolanacearum infestation, and the rootstock genotype affected fruit size distribution. Rootstocks presented higher resistance than did commercial bell pepper hybrids (scions) for 6 out of 10 Ralstonia isolates. AF-8253 and BRS Acará displayed an immunelike response to P. capsici, while Fortaleza was moderately resistant (25% symptomatic plants) and the bell pepper hybrids (scions) were susceptible (100% symptomatic plants). Rootstocks were immune to M. incognita race 1, but slightly (AF-8253 and BRS Acará) or moderately (Fortaleza) resistant to M. enterolobii. Grafting with BRS Acará, as well as with AF-8253 or Fortaleza, is recommended for managing bacterial wilt, Phytophthora blight, and root-knot nematodes.

Biochemical response of resistant and susceptible Capsicum spp. to Meloidogyne enterolobii

“…The consequences of such parasitism vary from mechanical damages (Pascholati & Dalio, 2018) caused by the entry and displacement of the nematode in the plant to the more complex changes that result from plant cell responses to the presence of the nematodes (Carneiro et al, 2016). When hosts are resistant to nematodes, several defence mechanisms can act or be triggered in the plant (Pinheiro et al, 2020; Ragassi et al, 2022). In the specific case of Meloidogyne invasion process, resistant phenotypes are associated with mechanical, physiological or biochemical barriers developed by the plant (Machaca‐Calsin et al, 2019; Pascholati et al, 2008).…”