title: The Potential of the MAGIC TOM Parental Accessions to Explore the Genetic Variability in Tomato Acclimation to Repeated Cycles of Water Deficit and Recovery.
abstract: Episodes of water deficit (WD) during the crop cycle of tomato may negatively impact plant growth and fruit yield, but they may also improve fruit quality. Moreover, a moderate WD may induce a plant "memory effect" which is known to stimulate plant acclimation and defenses for upcoming stress episodes. The objective of this study was to analyze the positive and negative impacts of repeated episodes of WD at the plant and fruit levels. Three episodes of WD (-38, -45, and -55% of water supply) followed by three periods of recovery ("WD treatments"), were applied to the eight parents of the Multi-Parent Advanced Generation Inter-Cross population which offers the largest allelic variability observed in tomato. Predawn and midday water potentials, chlorophyll a fluorescence, growth and fruit quality traits [contents in sugars, acids, carotenoids, and ascorbic acid (AsA)] were measured throughout the experiment. Important genotypic variations were observed both at the plant and fruit levels and variations in fruit and leaf traits were found not to be correlated. Overall, the WD treatments were at the origin of important osmotic regulations, reduction of leaf growth, acclimation of photosynthetic functioning, notably through an increase in the chlorophyll content and in the quantum yield of the electron transport flux until PSI acceptors (J 0 (RE1)/J (ABS)). The effects on fruit sugar, acid, carotenoid and AsA contents on a dry matter basis ranged from negative to positive to nil depending on genotypes and stress intensity. Three small fruit size accessions were richer in AsA on a fresh matter basis, due to concentration effects. So, fruit quality was improved under WD mainly through concentration effects. On the whole, two accessions, LA1420 and Criollo appeared as interesting genetic resources, cumulating adaptive traits both at the leaf and fruit levels. Our observations show that the complexity involved in plant responses, when considering a broad range of physiological traits and the variability of genotypic effects, represent a true challenge for upcoming studies aiming at taking advantage of, not just dealing with WD.
authors.affiliation: UR1115 Plantes et Systèmes de cultures Horticoles, INRAAvignon, France; Laboratoire de Physiologie des Fruits et Légumes EA4279, Université d'Avignon et des Pays du VaucluseAvignon, France.
authors.forename: Julie
authors.initials: J
authors.lastname: Ripoll
authors.affiliation: Laboratoire de Physiologie des Fruits et Légumes EA4279, Université d'Avignon et des Pays du Vaucluse Avignon, France.
authors.forename: Laurent
authors.initials: L
authors.lastname: Urban
authors.affiliation: UR1115 Plantes et Systèmes de cultures Horticoles, INRA Avignon, France.
authors.forename: Nadia
authors.initials: N
authors.lastname: Bertin
keywords: MAGIC population; S. lycopersicum L.; fruit quality; recovery period; water deficit