Combrink N.K.,Agricultural Research Council Institute for Tropical and Subtropical Crops ARCITSC |
Bijzet Z.,ARC ITSC |
Sippel A.D.,ARC ITSC |
Booyse M.,Agricultural Research Council Biometry ARC Biometry |
Labuschagne M.T.,University of the Free State
Acta Horticulturae | Year: 2015
Rind colour is the most important characteristic contributing to a fruit's appearance and therefore the improvement of rind colour has been a longstanding aim of citrus breeding programmes. However, due to lack of information on inheritance of rind colour in citrus, the breeder faces a difficult task when planning crosses for breeding new cultivars. Therefore a study was undertaken to investigate the variation in rind colour, as chroma coordinates L∗, a∗ and b∗, in six Mandarin families, where female parent Kiyomi tangor (Citrus unshiu × C. sinensis) was crossed with male parents Dancy, Hansen, Rishon, Roma, Shani and Sunburst Mandarins (C. reticulata). A significant level of variation was found between both the parents and the families for all the colour coordinates. A greater variation was found within the families than between the families, indicating a high level of genetic variation within the families, while the within tree variation was lower than the within family variation. All the families showed an improvement in the population for rind colour over the female parent Kiyomi for L∗ and b∗, while all the families except for the Kiyomi × Dancy family showed an improvement for a∗. The Kiyomi × Dancy and Kiyomi × Roma families were found to have a population with a lighter, more yellow-orange rind colour, while the Kiyomi × Hansen, Kiyomi × Rishon, Kiyomi × Shani and Kiyomi × Sunburst families had a population with a deeper, more orange-red rind colour. The intraclass correlation coefficient relevant to selection within the families was fairly low, indicating the variation was only partly genetic and the environment contributed to the phenotypic variation. Therefore a mean performance of multiple years data should be used for effective selection.