Resistance of eggplant grafted onto commercial Solanaceae rootstocks against Verticillium dahliae

A.S. Attavar, C.A. Miles
Verticillium wilt (caused by Verticillium dahliae Kleb.) can limit eggplant (Solanum melongena L.) production in Washington, USA, and elsewhere in the world, but grafting with resistant rootstock can be an effective management strategy. We evaluated commercial rootstock cultivars of tomato (‘Estamino’, ‘Shield’, ‘Survivor’) and eggplant (‘Java’, ‘Meet’), and heirloom tomato ‘Cherokee Purple’ as a rootstock in Mount Vernon, WA, using ‘Night Shadow’ eggplant as the scion. The experimental field site was naturally infested with V. dahliae, pre-plant soil population was 28 cfu g‑1 in 2016 and 5 cfu g‑1 in 2017, and treatments were inoculated with 5 mL of conidial suspension at transplanting to ensure infection; the suspension contained 8×106 (2016) and 2.35×106 (2017) conidia of V. dahliae mL‑1. ‘Night Shadow’/‘Estamino’ had low disease incidence and severity in 2016 at 75 days after transplanting (DAT), and in 2017 when plants were rated at 103 DAT, only disease severity was low for ‘Night Shadow’/‘Survivor’; non-grafted ‘Night Shadow’ had the highest disease incidence and severity both years. ‘Night Shadow’ grafted on ‘Estamino’ and ‘Survivor’ had the lowest stem populations of V. dahliae in 2016, and in 2017 ‘Night Shadow’ grafted on ‘Cherokee Purple’, ‘Java’, and Survivor’ had the lowest stem colonization. Weight of fruit plant‑1 was greatest for ‘Night Shadow’ grafted on ‘Meet’ and ‘Survivor’ in 2016 and for ‘Night Shadow’/‘Cherokee Purple’ in 2017. Fresh above ground plant biomass was greatest for ‘Night Shadow’/‘Estamino’ in 2016 and for ‘Night Shadow’/‘Cherokee Purple’ in 2017. Thus, grafting tended to reduce both disease incidence and severity, and increase yield and above ground plant fresh biomass, but grafting combinations that reduced disease incidence and severity did not necessarily increase yield or biomass. In conclusion, grafting could benefit eggplant production in Verticillium wilt infested fields in Washington, and tomato cultivars with resistance to Verticillium wilt could potentially function as rootstocks, thus reducing the cost of purchasing rootstock seed.
Attavar, A.S. and Miles, C.A. (2021). Resistance of eggplant grafted onto commercial Solanaceae rootstocks against Verticillium dahliae. Acta Hortic. 1302, 147-154
DOI: 10.17660/ActaHortic.2021.1302.20
https://doi.org/10.17660/ActaHortic.2021.1302.20
Verticillium wilt, yield, pathogen inoculation, stem colonization, biomass
English

Acta Horticulturae