In order to analyse the functional diversity of genetic resources, the team has developed, or worked with partners to develop phenotyping methods. Such is the case for coumarin and furanocoumarin contents (Dugrand et al., 2013), polyphenol contents (Durand-Hulak et al. 2015) and volatile compound contents of leaves (Sutour et al., 2017). Some ways of assessing tolerance of saline stress have also been developed (Hussain et al., 2012; Ben Yahmed et al., 2016). An analysis of the coumarin and furocoumarin contents (Dugrand-Judek et al. 2015), along with carotenoids (Fanciullino et al. 2006a), for the different species of Citrus revealed some diversity structures that are phenotypically closely linked to that of genetic diversity. Analyses of essential oil compounds from leaves and fruit zests highlighted some specificities of horticultural groups such as the kumquats (Sutour et al. 2015, 2016), mandarins (Fanciulino et al. 2006b), citrons (Venturini et al., 2010; Luro et al. 2012) and grapefruits (Paoli et al. 2016). They also revealed major phenotypic diversity within the ancestral taxa, probably linked to the central role of sexual hybridization in their within-species diversification. Physiological reactions to environmental stress also bear witness to the major role played by the evolution of the species complex in how the diversity of adaptation traits is organized. This is particularly the case for tolerance of saline stress (Hussain et al. 2015; Ben Yahmed et al. 2015a), water deficits (Ben Yahmed et al. 2015b), or oxidative stress (Santini et al. 2012, 2013).

References cited

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