Because coffee is a tree crop that takes 2-3 years to mature, breeding new varieties of coffee has traditionally been a slow process. It can take 20 or more years to bring a new variety to market.
But we know that new varieties are needed, and needed quickly, to meet the challenges of the 21st century—changing weather patterns, increased temperatures, and new disease and insect prevalence. The land available to grow Arabica coffee is also expected to dramatically shrink in coming years, meaning coffee trees must become more productive to meet increasing demand. Without better planting material, the coffee industry faces a potentially disastrous decline in Arabica supply in the coming decades.
The “low-hanging fruit” in coffee breeding is the concept of heterosis, or hybrid vigor. Generally in plant breeding, the greater the genetic distance between the two parents of hybrid offspring, the more “vigorous” the child will be. In coffee, heterosis frequently translates to productivity, uniformity, and better vegetative growth.
WCR has recently completed an exhaustive study of the genetic diversity of 826 Arabica plants that allowed us to do two key things. First, we were able to identify the 100 most genetically diverse Arabicas, called the Core Collection, which are now being grown as an essential new reservoir of genetic diversity for coffee breeders. The study also allowed us to determine how genetically different the plants are from one another. This “genetic distance matrix” is an essential tool to exploit hybrid vigor.
Working regionally with local coffee breeders, WCR’s breeding team holds workshops to determine what qualities are preferred in new varieties—resistance to specific disease, tall or dwarf stature, altitude suitability—to inform the selection of parent plants for hybrid crosses.
Using the genetic distance matrix, we can take existing high-performing varieties known for desired traits like quality (e.g., Geisha) or disease resistance (e.g., Obata), and locate mates that are genetically distant to maximize hybrid vigor—yield—in the offspring.
Currently in Central America, three groups of crosses (totaling 66 crosses) have been made. Plants from the first wave of 46 crosses were transferred to the field in 2017, where they are being observed for performance, including rust resistance and drought tolerance. The plants are also being shipped to Rwanda for testing in East Africa. More crosses will be made through regional breeding hubs in Central America and Africa in the coming years.
Using new breeding tools like the WCR Core Collection and Arabica genetic distance matrix, we can accelerate the creation of high-performing varieties for farmers. WCR will be able to test F1 crosses initiated in 2015 through 2018-2020, bringing better varieties to market in as few as five years.