As genetic factors affect strawberry (Fragaria ×ananassa Duch.) fruit development and quality, changes in metabolite concentrations were studied during fruit development of four strawberry cultivars grown in the field: three commercial cultivars (Capitola, Elsanta and Dover) and a genotype from Centre Interrégional de Recherche et d'Expérimentation de la Fraise, France (`CF1116'). Major and minor metabolites changed with development. The two strawberry cultivars with the highest starch content at early stages, `Capitola' and `Elsanta', also had the highest fruit weight at harvest. There was no correlation between strawberry weight and osmolarity. At maturity, significant differences were observed among cultivars for most of the metabolites studied. `Capitola' and `Elsanta' responded similarly for most measured variables. `CF1116' was characterized by high juice osmolarity and high sucrose, inositol, glutamine, arginine and alanine concentrations, and low citrate and malate concentrations. `Dover' was characterized by a high galactose concentration and low asparagine and alanine concentrations. Organic acid differences among cultivars appeared early during development, while differences in soluble sugars appeared during maturation. The developmental pattern of each amino acid varied among cultivars. Timing of the biochemical differences observed among cultivars provides some information on their metabolic origin.
Annick Moing, Christel Renaud, Monique Gaudillère, Philippe Raymond, Philippe Roudeillac, and Béatrice Denoyes-Rothan
Annick Moing, Christel Renaud, Hélène Christmann, Lydie Fouilhaux, Yves Tauzin, Anne Zanetto, Monique Gaudillère, Frédéric Laigret, and Jacques Claverie
Rain-induced fruit cracking is a limiting factor for sweet cherry (Prunus avium L.) growers in many production areas. Although many studies have concerned this complex phenomenon, the basic mechanisms involved in fruit cracking remain unclear. We re-examined the relations between osmotic potential and cracking susceptibility in cherry fruit by comparing the osmotic contribution of the major metabolites separately in flesh and skin, in four cultivars (with different levels of susceptibility to cracking) at four stages of development. Several differences were observed between flesh and skin revealing compositional gradients in the fruit tissues. Acidity and malate concentrations were higher in flesh than in skin for all stages. The absolute value of osmotic potential was higher but the contribution of the sum of sugars to osmotic potential was lower in flesh than in skin. As determined using fruit immersion test, `Fermina' and `Regina' were less susceptible to fruit cracking than `Lapins' and `Brooks'. At commercial maturity when fruit susceptibility to cracking was highest, no clear difference appeared between `Brooks' and `Lapins' compared to `Regina' and `Fermina' for flesh or skin osmolarity and for the contribution of the major sugars or organic acids to skin and flesh osmotic potential.