ABSTRACT
Citriculture is widespread worldwide and economically important in the subtropical and tropical subtropical regions where climate and soil conditions are adequate. Due to the large range and remote centers of origin, the control of the origin of citrus is difficult. Citrus genetic improvement tools were divided into mainly two categories: traditional (introduction, selection, and hybridization) and non-traditional (mutation, somatic cell hybridization, and genetic engineering). It took hundreds of thousands of years for wild Asian citrus to develop into modern varieties. Despite the fact that citrus breeding is difficult, various breeding programs across the world have achieved tremendous success in applying traditional and modern approaches to genetic improvement and cultivar development. Aside from traditional breeding for the development of new scion and rootstock varieties, embryo rescue, protoplast fusion, molecular markers, marker-assisted selection, and genetic transformation are frequently used in citrus breeding around the world, especially with the effective use of developing biotechnology. In this chapter, we briefly tried to explain current citrus genetic improvement efforts in terms of both scion and rootstock improvements.
