Cut rose breeding: Progress, stability or decline? - A review

Abstract

Hybrid Tea cut roses, the most important ornamental crop, covers about 20,000 ha worldwide. Growers are provided with roughly 150 new cultivars per year, by not more than ten prominent rose breeders. To create these cultivars, breeders raise about one million seedlings annually, by crossing 200-500 progenitors per enterprise. An overlap of 50% progenitors is estimated, while the other half descends from the first one. Each year, older progenitors are replaced by new ones that are selected from newly introduced cultivars. The HT cut rose gene pool therefore consists of genotypes that become more closely related with each generation. Breeding with related genotypes is a form of inbreeding, which in populations is shown by more similar seedlings, probably more rogues, the need to increase population size and, ultimately, loss of vigour of new cultivars. Escape from inbreeding is recommended by application of specialized seedling selection, the use of once-famous varieties, inter specific crossing, mutation breeding or deliberate inbreeding.