Screening morpho-physiological and yield traits for improving grafted tomato transplant performance under stresses

D.I. Leskovar, D. Djidonou, S. Bhattarai, C. Lee, F.M. Alves, J.T. Harvey, K. Crosby
Increasing global population, climate change and land use necessitates sustainable crop production strategies. However, improving tomato (Solanum lycopersicum) production in extreme environments is challenging. Our team has conducted a series of field, high tunnel and growth chamber tomato studies aimed at 1) screening and selecting thermotolerant scions and rootstocks genotypes based on yield performance, 2) screening and selecting potential Texas A&M University TAMU tomato rootstocks for disease resistance, and 3) understanding physiological-biochemical trait responses to abiotic stresses. We identified chlorophyll fluorescence and leaf electrolyte leakage as traits most correlated with total yield in field conditions and heat stress resistance in controlled conditions. In controlled environment grafting experiments, we demonstrated that ‘Maxifort’ rootstocks improved and reduced contents of various heat stress-responsive enzymes, under optimal and high heat conditions compared to ungrafted controls but did not influence leaf enzyme contents. Lastly, we explored the potential of rootstocks of tomato wild relatives (S. pennellii, S. peruvianum) to improve scion drought resistance as well as potential TAMU rootstocks as source of resistance traits for major tomato diseases and to increase fruit yield. Wild type grafted scions exhibited improved water potential, leaf relative water content, water use efficiency, net photosynthetic rate and malondialdehyde content, but lower proline content, compared to ‘Multifort’ grafted and self-grafted controls. Taken together, our program has identified tomato cultivars well-suited to grafting and cultivation in extreme environments as well as physiological traits associated with improved stress resistance, that warrant additional attention in future experimental and breeding endeavors.
Leskovar, D.I., Djidonou, D., Bhattarai, S., Lee, C., Alves, F.M., Harvey, J.T. and Crosby, K. (2023). Screening morpho-physiological and yield traits for improving grafted tomato transplant performance under stresses. Acta Hortic. 1365, 101-108
DOI: 10.17660/ActaHortic.2023.1365.13
Solanum lycopersicum, heat tolerance, drought stress, electrolyte leakage, grafting, tomato wild relative

Acta Horticulturae