Solanum rootstock biodiversity to deal with holoparasitism and fertilizer use efficiency

Tomato (Solanum lycopersicum L.) is one of the most widespread and economically important crops worldwide and is exposed to multiple biotic and abiotic stresses such as soilborne diseases and nutrient deficiencies.
While root broomrapes holoparasitism reduces yield >70% in many regions, the crop also faces nutrient deficiencies in poor soils, while intensive use of fertilizers (mainly NPK) has detrimental economic and environmental consequences.
Breeding is one of the most promising strategies to alleviate these problems, but both knowledge about the molecular and genetic bases of fertilizer use efficiency (FUE) and tolerance to parasitism, as well as availability of sources of resistance are very limited.
Grafting provides a rapid and direct tool to transfer traits of agronomic interest from the rootstock to commercial cultivars through local (root) and systemic (root to shoot) mechanisms, which enables an empirical perspective to alleviate these problems in commercially graftable species as the tomato.
Grafting also offers specific root-directed approach to gain insights into the physiological, molecular, and genetic components of such resistances.
To pursue this objective, a set of experimental accessions from Solanum sp. has been studied for providing tolerance to the parasitic plant Phelipanche ramosa (L.), and increased FUE to susceptible tomato cultivars, when used as rootstocks. Solanum biodiversity includes the wild species Solanum pennellii, S. pimpinellifolium, S. habrochaites, S. galapagense, S. peruvianum, S. chilense, S. chmielewskii; some of their crosses with the domesticated tomato S. lycopersicum; eggplants S. melongena and S. aethiopicum, and some mutants affected in strigolactone production.
The results obtained confirm that selected lines for resistance to low NPK nutrition and broomrape infection can transfer the observed tolerance to commercial cultivars through grafting, which confirms that rootstock breeding is a promising strategy for improving for those important agronomic traits.
The underlying physiological and molecular basis of such traits is being studied.

IV Asian Horticultural Congress – AHC2023

P.A. Martínez-Melgarejo, M. Ormazabal, J.A. López-García, J.J. Guerrero-Franco, J.A. Martín-Rodríguez, C. Martínez-Andújar, F. Pérez-Alfocea

nutrient use efficiency, parasitic plants, plant hormones, root system architecture, tomato, vegetable grafting

https://doi.org/10.17660/ActaHortic.2024.1404.69