Investigating the Parentage of 'Orri' and 'Fortune' Mandarin Hybrids

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. 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' has 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 (ABS) might be expected, but it is more likely to have inherited a high degree of susceptibility; yet 'Orri' appears to be immune to ABS. 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 ABS 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. 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 reinterpret heritability studies on ABS susceptibility of mandarins and their hybrids.