Effect of Rootstock on the Fruit Quality of Mandarins "Clemenules" and "Tango", and Blood Oranges "Tarocco Rosso" and "Moro"

Abstract

This Thesis also includes a study about this variety's postharvest behavior as no data are available for our crop conditions. The 'Tango' mandarin presented outer chilling injury symptoms after being stored for 20 days at 1°C and 5°C. A microstructural study was done to characterize the alteration caused by low temperatures. The Forner-Alcaide 5 rootstock fruit showed a lower chilling injury incidence. Storage at 9°C did not compromise this variety's external or internal quality. Among oranges, demand for blood oranges to be eaten fresh has grown in recent years, basically due to their high content in anthocyanins and their positive effect for human health. To assess the effect that rootstock had on blood oranges, two reference varieties were taken, 'Moro' and 'Tarocco Rosso', grafted onto eight rootstocks. Internal quality was strongly influenced by harvest time, which was more evident for 'Moro'. In both varieties, rootstock affected changes in the quality parameter studied during maturity. In 'Moro', juice color faded as anthocyanins degraded, and rootstocks C-35 Citrange, Macrophylla and Volkameriana showed the most marked reduction. Such anthocyanin degradation was related to the change in temperature that took place during the harvest period. In 'Tarocco Rosso', anthocyanins did not undergo degradation, which suggests that this variety is less sensitive to changes in ambient temperature. In this variety, rootstocks Forner-Alcaide 5 and Forner-Alcaide 13 gave fruit with a higher content of anthocyanins and sugars.This Thesis also includes a study of the suitability of refrigerated conservation of two blood orange varieties: 'Tarocco Rosso' and 'Sanguinelli'. Although storage at any tested temperature (1°C, 5°C and 9°C) did not affect internal quality for 45 days, fruit displayed chilling injury symptoms at 1°C, with a higher incidence for 'Sanguinelli' than for 'Tarocco Rosso'. Both varieties can be stored between 5°C and 9°C for 30 days for 'Sanguinelli' and for up to 45 days with 'Tarocco Rosso'. ABREVIATIONSRootstocks FA13 Forner-Alcaide 13 [Citrus reshni x Poncirus trifoliate (L.) Raf no 13] FA5 Forner-Alcaide 5 [Citrus reshni x Poncirus trifoliate (L.) Raf no 5] CC Citrange Carrizo [Citrus sinensis (L.) Osb.×Poncirus trifoliate (L.) Raf.] C35 Citrange C-35 [Citrus sinensis (L.) Osb.xPoncirus trifoliata (L.) Raf.] CL Cleopatra mandarin (Citrus reshni Hort. Ex Tan) M Macrophylla [Citrus macrophylla Wester] CT 'Swingle' Citrumelo [Citrus paradisi (L.) × Poncirus trifoliate (L.) Raf.] VK Volkameriana (Citrus volkameriana Ten. and Pasq.) V17 Forner-Alcaide V17 [Citrus volkameriana Ten & Pasq. x Poncirus trifoliata (L.) Raf. no V17] FA 2324 Forner-Alcaide 2324 (Hybrid of 'Troyer' citrange and Cleopatra mandarin FA 418 Forner-Alcaide 418 [Troyer citrange × common mandarin (C. deliciosa Ten.] TC 'Troyer' citrange [Citrus sinensis (L.) Osb.×Poncirus trifoliate (L.) Raf.] SO Sour Orange (Citrus aurantium L.) General IVIA Instituto Valenciano de Investigaciones Agrarias CTV Citrus Tristeza Virus TSS Total Soluble ...