Citrus protoplast fusion and evaluation of the somatic hybrid ?Hamlin? sweet orange + ?Montenegrina? mandarin for resistance to Xanthomonas axonopodis pv. citri and Xylella fastidiosa

by Pavan, Alexandra

Abstract (Summary)
This research aimed to produce new somatic hybrid combinations between sweet orange (Citrus sinensis) with mandarins (C. reticulata, C. reshni, C. Sunki, C. deliciosa), tangors (C reticulata x C. sinensis) or ?Orlando? tangelo (C. reticulata x C. paradisi), and also evaluate the somatic hybrid ?Hamlin? sweet orange (Citrus sinensis) + ?Montenegrina? mandarin (Citrus deliciosa) for resistance to Xanthomonas axonopodis pv. citri and Xylella fastidiosa. Protoplast sources included embryogenic calli or suspension-culture derived calli, and leaves collected from plants cultivated in vitro or in screenhouses. After protoplast isolation, embryogenic protoplasts were chemically fused by polyethylene glycol (PEG) with mesophyll-derived non-embriogenic protoplasts. Fusion-derived calli were further cultured to embryo induction, germination, and plant regeneration. Regenerated plants were individually rooted or micrografted, and further acclimated in screenhouse. Somatic hybridization was confirmed by analysis of leaf morphology, molecular analysis by RAPD markers, ploidy determination by chromosome counting or flow cytometry. The producion of the somatic hybrids ?Hamlin? sweet orange + ?Montenegrina? mandarin and ?Hamlin? sweet orange + ?Dancy? mandarin was confirmed. These hybrids may have complementary traits from both progenitor and be used directly as scion cultivars or as parental lines in scion improvement programs. ?Hamlin? sweet orange + ?Montenegrina? mandarin somatic hybrid was resistant to Xanthomonas axonopodis pv. citri and Xylella fastidiosa.
This document abstract is also available in Portuguese.
Bibliographical Information:

Advisor:Francisco de Assis Alves Mourão Filho; Maria Angélica Pereira de Carvalho Costa; Beatriz Madalena Januzzi Mendes; Francisco de Assis Alves Mourão Filho

School:Universidade de São Paulo

School Location:Brazil

Source Type:Master's Thesis

Keywords: Asian citrus canker cultivar improvement


Date of Publication:08/28/2006

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