Which coffee varieties are resistant to leaf rust? Control of coffee leaf rust and its harm to economy

When coffee rust first appeared in Brazil, almost all coffee in America, even almost all commercially produced coffee, can be traced back to a tree planted in King Louis XIV's greenhouse in 1713. The genetic consistency of commercial coffee production constitutes (and will continue to constitute) a significant potential risk of devastating epidemics.

It has been known for some time that wild coffee species are resistant to coffee rust. So far, nine resistance genes have been identified, mainly from C. canephora and C. liberica (Fig. 12). One challenge for breeders is to combine rust resistance with good agronomic properties and quality coffee. The next challenge is to deploy these resistance genes in such a way that they are not immediately overcome by the new race of H.vastatrix. So far, more than 40 different races of H.vastatrix have been identified, and some new hybrids can attack previously resistant hybrids. New rust continues to appear. In order to reduce the selection of poisonous varieties, breeders at Cenicafe, Colombia's National Coffee Research Center, created a compound variety with uniform agronomic characteristics and coffee quality, but mixed with rust resistance genes.

A disturbing development in coffee breeding is the sharp loss of genetic diversity of wild coffee species. There is little genetic diversity in coffee in southwestern Ethiopia, where small grains evolve outside the rainforest. These forests have shrunk to less than 1/10, thanks to logging, fuelwood harvesting and expanded cultivation driven by population growth. The Ethiopian Institute for Biodiversity Conservation and Research is working to preserve the rest, and the Ethiopian Government has banned the export of coffee plants and coffee seeds from the country.

Meaning

Coffee rust can lead to premature leaf loss, which reduces photosynthesis and weakens trees. As the next season of berries will bear fruit on the branches of this season, the rust of this season will reduce the yield of the next season. Depending on the weather of the current season and the yield and infection levels of the previous season, yields may vary by as much as 10 times from one season to the next. Severe infection can cause branches to die and even kill trees (figure 13).

Economic impact

Coffee rust is the most important coffee disease in the world economy. In terms of monetary value, coffee is the most important agricultural product in international trade. Even a small decline in coffee production or a small increase in production costs caused by rust can have a huge impact on coffee producers, support services and even banking systems in countries whose economies are entirely dependent on coffee exports.