Tomato organic management and improvement project (TOMI): an interdisciplinary approach to managing foliar diseases in tomato

L. Hoagland, M. Colley, J. Dawson, J. Davis, D. Egel, S. Gu, T. Mengiste, J. Myers, J. Zystro
Managing foliar diseases, including late blight (LB) and early blight (EB), is one of the biggest challenges facing organic tomato growers. New resistant hybrid cultivars are available, but organic growers often plant heirloom varieties because they are perceived to have superior flavor. The tomato organic management and improvement project (TOMI) aims to address this challenge by 1) selecting improved tomato cultivars using a participatory breeding approach, 2) improving understanding of factors that regulate induced systemic resistance (ISR) and selecting tomato cultivars with multiple forms of resistance, and 3) identifying biofungicide and biostimulant combinations that control foliar diseases while reducing the amount of copper fungicide applied. Breeding populations are being screened alongside commercial controls in organic nurseries at university research stations in Indiana, North Carolina, Oregon and Wisconsin, USA, during 2015 and 2016. Plants from the best families were recombined during winter 2015. Further screening and selection of lines for potential release will be conducted in collaboration with organic growers in on-farm trials during 2017 and 2018. Genotypes representing wild-type, landrace, modern and advanced breeding lines are being tested for responsiveness to ISR to LB and EB using several plant-growth-promoting microorganisms. One responsive genotype will be included in an RNA-seq experiment to improve understanding of the mechanisms that regulate ISR and design markers to improve germplasm screening and to quantify ISR expression in field trials. Advanced breeding lines are being screened for quantitative resistance to LB using molecular markers and quantitative resistance to LB and EB using detached-leaf assays. Organic biofungicides and biostimulants are being tested, alone and in combination, for their potential to control EB and LB in greenhouse trials. The best combinations are being tested in field trials in Indiana and North Carolina during 2016 and 2017. Additional information about this project can be accessed at
Hoagland, L., Colley, M., Dawson, J., Davis, J., Egel, D., Gu, S., Mengiste, T., Myers, J. and Zystro, J. (2018). Tomato organic management and improvement project (TOMI): an interdisciplinary approach to managing foliar diseases in tomato. Acta Hortic. 1207, 203-210
DOI: 10.17660/ActaHortic.2018.1207.27
Alternaria solani, Bacillus, compost tea, Gliocladium, mycorrhiza, Phytophthora infestans, polypeptide, priming, Pseudomonas, rhamnolipid, silicon, Trichoderma

Acta Horticulturae