DNA Markers for Coffee Tree Breeding

Abstract

Coffee cultivation in the world has benefited greatly from the successful breeding programmes, which have given the farmers productive cultivars adapted to specific cropping conditions. For example, presently in Brazil the improved arabica coffee cultivars (Coffea arabica L.) produces three to four times more than the cultivars used in the past. However, yield in this species seems to have reached a plateau, which is hard to overcome. Examples are the yield of improved Mundo Novo, Catuaí Vermelho and Catuaí Amarelo lines, which are still the most productive today. Therefore, one of the great challenges for the breeders is to increase the yield of the present cultivars. Another great challenge for the breeder is to transfer genes to improve coffee resistance/tolerance to disease and pests, since the arabica species is very susceptible to them. Although C. arabica has twice the number of chromosomes than the other species in the genus, some inter-specific hybridization has been successfully exploited. The world wide occurrence of coffee tree rust (Hemileia vastatrix Berk.et Br.) for example, and the damage it causes, have aroused the interest of the breeder in finding resistant arabica coffee cultivars by natural or artificial hybridization with Coffea canephora Pierre. Breeding by hybridization in coffee, as in other plants, requires identification of genetic variability for the characteristics to be improved, the choice of the most promising hybridization, and the application of methods, which favour selection of superior hybrids, lines or populations. In this context, DNA marker technologies have been proposed as useful tools for research programs. This technologies may be of great potential to help breeding, especially in coffee, because it is a perennial crop with a long juvenile period.