Determination of Genome Size Differentiation and Ploidy Levels in Some Citrus Rootstock Populations

Determining the ploidy level of plant material used in breeding is important, especially for biotechnological applications. The genetic diversity in citrus enables the development of rootstocks and cultivars adapted to various climates and soils. Various suitable rootstocks are used in commercial citrus production.This study was conducted to determine the genome size and ploidy levels of citrus rootstocks widely used worldwide using flow cytometry. The rootstocks used in the study included Gou-Tou, C-35, Troyer citrus, Taiwanica, Citremon, Yuzu, Sunki mandarin, Flying Dragon, Yuma citrus, Macrophylla and Chinese orange. Fresh leaf tissue from each rootstock was mixed with triploid Tahitian lemon leaf tissue, used as a standard species, and cell nuclei were isolated. The cells stained with propidium iodide were analysed by flow cytometry, and histograms and cytograms were obtained. According to the results, although all species had diploid genome sizes, differences were observed between species in terms of genome volume. Yuzu seedlings were found to have the largest genome size (0.808 pg/2C), while Flying Dragon trifoliate had the smallest genome size (0.700 pg/2C).