Fresh Citrus fruit and processed products are major household items worldwide. Most well-known cultivars are clones that have arisen by chance, and a century of effort in conventional plant breeding has added few new varieties, or even characteristics. This book, whose authors represent the main citrus-growing regions of the world, explains why, and outlines new approaches, which may help towards success in future.

The first two chapters introduce the problems of Citrus breeding: apomoxis (nucellar embryony, explained in chapter 5) is widespread in the genus, and while production of genetically uniform rootstocks relies on it, identifying zygotic embryos from cross-pollination can be a problem, compounded by a long juvenile period and the space required for testing trees. Further, consumers prefer seedless fruit, mostly achieved through triploidy (chapters 6–8). Chapters 3 and 4 cover taxonomy and germplasm resources, while work particularly for disease resistance, through individual genes and transformed genomes (for example, the citrus tristeza viral coat protein gene) is described in chapters 13 and 14. In vitro shoot tip grafting is useful for producing disease-free material, and for regeneration of plants after cellular manipulation (17). Other techniques covered include somaclonal variation (9), somatic hybridization (10), microprotoplasts (11), marker-assisted selection (12) and mutation breeding (16). There have been some achievements and many plants are under test, although a lot of the examples given are from other crops.

The book is well edited and presented, and should be useful to citrus scientists and growers, and breeders of other crops.