Articles
Host resistance in commercial tomato cultivars to manage Phytophthora infestans
Article number
1445_27
Pages
193 – 200
Language
English
Abstract
Late blight, incited by Phytophthora infestans, is a devastating disease of tomato.
Systemic and contact fungicides are relied upon for conventional production, but effective options are limited for organic growers.
In 2018 and 2019, 12 and 22 tomato cultivars, respectively, were tested under growth chamber, field, and greenhouse conditions for late blight resistance.
Plants were inoculated with 1×105 (greenhouse and growth chamber) or 1×104 (field) sporangia mL‑1 suspensions of an isolate of P. infestans clonal lineage US-23. In the growth-chamber study, the lowest disease severity at the final assessment at 14 days after inoculation (<20%) was observed in ‘Matt’s Wild Cherry’ and ‘Tomato Stellar’, with significantly less disease than all other cultivars.
The relative area under the disease progress curve (rAUDPC) data indicated these cultivars were significantly less susceptible than all other cultivars except for ‘Mountain Magic’ which was similar to ‘Matt’s Wild Cherry’. In greenhouse experiment 1 (2019), ‘Mountain Magic’, ‘Tomato Stellar’, and ‘Mountain Merit’ had the least amount of foliar disease severity (0-8.0%) for each observation date.
In greenhouse experiment 2 (2019), ‘Iron Lady’, and ‘Defiant’ had the lowest disease severity but were similar to ‘Lemon Drop’, according to the rAUDPC data.
For the field experiment (2019), 11 of the cultivars included in the study had foliar disease severity <5% on the final observation date.
According to the rAUDPC data, ‘Iron Lady’ and ‘Defiant’ had the lowest disease severity but were similar to ‘Lemon Drop’. ‘Lemon Drop’, ‘Cherry Bomb’, and ‘Fantastico’ were similar to each other; ‘Plum Regal’ was similar to ‘Cherry Bomb’ and ‘Fantastico’. Disease control in tomatoes grown for both organic and conventional markets could be advanced by using tomato cultivars with resistance to P. infestans.
Systemic and contact fungicides are relied upon for conventional production, but effective options are limited for organic growers.
In 2018 and 2019, 12 and 22 tomato cultivars, respectively, were tested under growth chamber, field, and greenhouse conditions for late blight resistance.
Plants were inoculated with 1×105 (greenhouse and growth chamber) or 1×104 (field) sporangia mL‑1 suspensions of an isolate of P. infestans clonal lineage US-23. In the growth-chamber study, the lowest disease severity at the final assessment at 14 days after inoculation (<20%) was observed in ‘Matt’s Wild Cherry’ and ‘Tomato Stellar’, with significantly less disease than all other cultivars.
The relative area under the disease progress curve (rAUDPC) data indicated these cultivars were significantly less susceptible than all other cultivars except for ‘Mountain Magic’ which was similar to ‘Matt’s Wild Cherry’. In greenhouse experiment 1 (2019), ‘Mountain Magic’, ‘Tomato Stellar’, and ‘Mountain Merit’ had the least amount of foliar disease severity (0-8.0%) for each observation date.
In greenhouse experiment 2 (2019), ‘Iron Lady’, and ‘Defiant’ had the lowest disease severity but were similar to ‘Lemon Drop’, according to the rAUDPC data.
For the field experiment (2019), 11 of the cultivars included in the study had foliar disease severity <5% on the final observation date.
According to the rAUDPC data, ‘Iron Lady’ and ‘Defiant’ had the lowest disease severity but were similar to ‘Lemon Drop’. ‘Lemon Drop’, ‘Cherry Bomb’, and ‘Fantastico’ were similar to each other; ‘Plum Regal’ was similar to ‘Cherry Bomb’ and ‘Fantastico’. Disease control in tomatoes grown for both organic and conventional markets could be advanced by using tomato cultivars with resistance to P. infestans.
Authors
D.E. Perla, M.K. Hausbeck
Keywords
late blight, oomycete, tomato, genetic resistance
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