Variation of fruit size and shape in Kiyomi tangor families

Fruit size and fruit shape contribute to a fruit's appearance and influence the fruit quality and marketability. They are therefore important characteristics to be considered when breeding new and improved citrus cultivars. The aim of this study was to investigate the genetic variation in the progenies of six mandarin families, where female parent Kiyomi tangor (Citrus unshiu × Citrus sinensis) was crossed with male parents Dancy, Hansen, Rishon, Roma, Shani and Sunburst mandarins (Citrus reticulata). Fruit size and fruit shape data was used to quantify the genetic variability within and between the families, in order to study the relationships between the hybrids and the parents and gain an understanding of how these characteristics are inherited. A significant level of between parent and between family variation was found for the fruit characteristics studied. The within family variation was greater than the between family variation. The within tree variation was lower than the within family variation, for fruit height and fruit width, while fruit shape did not show a large difference between the within tree and within family variation. The parents and families showed a significant year and year × parent variation for fruit height and fruit width. The Kiyomi × Dancy, Kiyomi × Rishon and Kiyomi × Shani families showed an increase in fruit size over the male parent. The Kiyomi × Rishon family had a larger fruit size than the other families, showing a greater increase in the population. Selection for an increase in fruit size is therefore possible within this material.