Development context and challenges

Citrus fruits are the second largest fruit industry in the world after bananas and plantains. They originate from Asia, but are grown today between the 40th parallels North and South in highly varied production and marketing systems. These different citrus industries have to cope with increasing biotic and abiotic constraints, along with the expectations of society in terms of quality (sensory, nutritional, food safety) and environmental friendliness. Varietal innovation helps to provide answers to certain major challenges facing the citrus industries. The SEAPAG team works together with stakeholders in the public and private sectors to develop varietal innovation projects designed to contribute to the sustainability of citrus fruit growing in different Mediterranean and tropical production basins. The contexts and challenges of the citrus fruit supply chains involved are diverse, and breeding (ideotype) objectives can differ. Beyond the confines of the team, the efficient implementation of such projects and the effective dissemination of innovation to producers means bringing into play and integrating skills in the fields of socio-economic analysis, the physiology of adaptation, plant pathology and quality characterization.

Scientific challenges

The aims of the research undertaken by the SEAPAG team are to acquire and integrate knowledge in the field of reproductive biology, the physiology of adaptation to abiotic stress, disease resistance and quality build-up in order to optimize Citrus genetic improvement. Vegetative propagation, the interspecific origins of most modern varieties, and the merits of triploidy for creating seedless varieties, and of the tetraploidy of rootstocks for greater plasticity, raise some original research issues regarding phylogenomic structures, the functioning (meiosis, expression, etc.) of complex genomes, and phenotype elaboration. In terms of creation/selection, vegetative propagation enables the multiplication of any elite genotype whatever its genomic structure. Ideotypes defining some of the most economically important horticultural groups (oranges, grapefruits, lemons, limes, etc.) are based on highly heterozygous genomic structures of interspecific origin. They can be bred today using phylogenomic reconstruction strategies, or genome edition for one-off corrections of their phenotype.