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Research Project: Breeding Stone Fruit Adapted to the Production Environment of the Southeastern United States

Location: Fruit and Tree Nut Research

Title: Investigating the Parentage of ‘Orri’ and ‘Fortune’ Mandarin Hybrids

Author
item BARRY, GRAHAM - Xlnt Citrus Company
item GMITTER, FRED - University Of Florida
item Chen, Chunxian
item ROOSE, MIKEAL - University Of California
item FEDERICI, CLAIRE - University Of California
item McCollum, Thomas

Submitted to: Acta Horticulturae
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/22/2014
Publication Date: 1/20/2015
Publication URL: http://www.actahort.org/books/1065/
Citation: Barry, G.H., Gmitter, F.J., Chen, C., Roose, M.L., Federici, C.T., Mccollum, T.G. 2015. Investigating the Parentage of ‘Orri’ and ‘Fortune’ Mandarin Hybrids. Acta Horticulturae. 1065:449-456.

Interpretive Summary: The pollen parent of germplasm and cultivars appears often misidentified because outcross pollination is so common when interspecific sexual compatibility is high. Now informative DNA molecular markers can be used as a reliable tool to authenticate questioned cultivars, for example, “Orri” and “Fortune” mandarins in this study. Two independent marker analysis confirmatively excluded the thought-to-be pollen parent of the two cultivars and revealed the most likely ones.

Technical Abstract: Germplasm characterization is now possible and more reliable using improved molecular markers and genomic tools. Previously citrus cultivars were primarily described according to their morphological or horticultural traits, but trueness-to-type can now be confirmed using molecular markers, thereby limiting inadvertent cultivar misidentification. However, following routine testing the reported parentage of two mandarin hybrids is now questioned. ‘Orri’ mandarin is derived from ‘Orah’ mandarin by induced mutation, and was reportedly bred by crossing ‘Temple’ tangor and ‘Dancy’ mandarin. ‘Orri’ is prized in many European markets for its excellent organoleptic qualities, and other favorable traits. With ‘Dancy’ as the pollen parent, at least some degree of susceptibility of ‘Orri’ to Alternaria brown spot might be expected, but it is more likely to have inherited a high degree of susceptibility; yet ‘Orri’ appears to be immune to Alternaria brown spot. SSR analysis provided evidence that excludes ‘Dancy’ as the pollen parent of ‘Orah’. Further testing revealed the likely pollen parent candidate as ‘Kinnow’ mandarin. ‘Fortune’ mandarin was a popular late-maturing mandarin cultivar until the high incidence of Alternaria brown spot rendered the cultivar uneconomical to produce in certain citrus production regions. This exceptionally late, high quality, attractive cultivar is reported to have originated from a ‘Clementine’ mandarin x ‘Dancy’ cross made by Furr (USDA, Indio, California). ‘Fortune’ is used as a female parent in breeding programs. However, two independent molecular marker studies revealed that the pollen parent of ‘Fortune’ is possibly ‘Orlando’ tangelo and not ‘Dancy’. In both cases, the pollen parent of ‘Orri’ and ‘Fortune’ mandarin hybrids appears not to be ‘Dancy’ as published. This information will assist geneticists and breeders to re-interpret heritability studies on Alternaria brown spot susceptibility of mandarins and their hybrids.