Tomato and eggplant nitrogen utilization efficiency in Mediterranean environments
Nitrogen (N) is a major limiting factor for plant growth and crop yield in both natural and agricultural environments. For this reason, in the past decades, N fertilization has increased more than 20-fold in excess compared to crop requirement, causing massive environment and human health damages with elevated economic and ecological costs. Therefore, to minimize N input, an efficient fertilizer management together with the identification of high N-use efficient genotypes could be one of the main challenge to sustain high crop yields reducing environmental, economic and health costs. Thus, the improvement of Nitrogen use efficiency (NUE) by plants is becoming essential to maintain high crop yield under low N input, in a sustainable agriculture.
NUE defined as “grain production per unit of N available in the soil” is a complex trait, regulated by multiple interacting genetic and environmental factors, which includes two physiological components. Nitrogen Uptake Efficiency (NUpE), which describes the ability of plant to take up N from the soil, and Nitrogen Utilization Efficiency (NUtE), which indicates the ability of plant to assimilate, remobilize and use N to produce grain.
Tomato (Solanum lycopersicum L.) is the most important vegetable crops spread cultivated in Mediterranean regions. A major resilience of tomatoes appears increasingly of great interest for a better adaptation to more common abiotic stress conditions such as drought and N-limitation in soils. Eggplant (Solanum melongena L.) is another Solanaceous vegetable crop of increasing importance during the last years. It is a warm-weather crop mostly cultivated and consumed in many tropical and subtropical regions of the world.
Many biotechnological and genomic tools are available for the improvement of the most important Solanaceae as tomato, potato, eggplant and pepper. Improving NUE in tomato and eggplant is of particular importance, as large amounts of N fertilizer are required to obtain their best yield. Several studies on model species and crops highlighted natural variation for nitrogen uptake efficiency, nitrogen assimilation and root morphology in many crops. Thus, the identification of high NUE tomato and eggplant genotypes, and the identification of their contrasting physiological and molecular traits, could be used to provide tools for developing genomic-based breeding strategies.
SOLNUE aim is to provide knowledge and strategies for an ecological and sustainable vegetable cropping system by the reduction of nitrogen (N) fertilizer, using tomato and eggplant as target species. The results may be extended to other fruit vegetables. In particular, the main goal will be the identification of tomato and eggplant efficient genotypes in N-use in agreement with the EU policy about the agricultural sustainable practices. The development of high NUE genotypes is considered more challenging than targeting N applications, although more effective as a part of an integrated crops nutrient management.
The deliverables of SOLNUE will be 1) the identification and selection of tomato and eggplant genotypes contrasting for nitrogen use efficiency (NUE); 2) the improvement of knowledge on morpho-physiological and molecular traits in NUE-contrasting tomato and eggplant genotypes; 3) the genotyping and phenotyping of segregant populations for associations/QTL related to low nitrogen responses with special focus on eQTL controlling the response to low N-stress; 4) the setting up of genomic selection based on whole genome information.
Genomic prediction models for fruit production and quality will be proposed, based on the information on the populations evaluated and tested taking into account the impact of low N stress to foster the selection of novel high NUE varieties.
Prof Francesco Sunseri
Università Mediterranea di Reggio Calabria, AGRARIA, ITALY
Prof Jaime Prohens
Universitat Politècnica de València, Instituto de Conservación y Mejora de la Agrodiversidad Valenciana, SPAIN
Dr Giuseppe L. Rotino
Council for Agricultural Research and Economics, Research Centre for Genomics and Bioinformatics, ITALY
Mrs Frederique Bitton
INRA, BAP, FRANCE