Mutation Breeding in Arabica Coffee

Abstract

Coffee is a perennial (sub)tropical crop and one of the most valuable commodities globally. Coffee is grown by an estimated 25 million farmers, mostly smallholders, and provides livelihoods to about 125 million people. The Coffea genus comprises over 120 species. Two species account for nearly the entire world coffee production: C. arabica L. (Arabica coffee) and C. canephora Pierre ex A. Froehner (Canephora coffee) with the former supplying about 65% of the world’s consumption. Arabica coffee is a self-pollinated, amphidiploid species (2n = 4x = 44) whereas other Coffea species are diploid (2n = 2x = 22) and generally cross-pollinated. Induced mutagenesis using physical and chemical mutagens has been a successful strategy in producing over 3,300 mutant varieties in over 220 crop species with global impact. Spontaneous Arabica coffee mutants of significant economic importance have been found since the early 1900s, following the spread of Arabica coffee cultivation across the globe. However, Arabica coffee has so far not been improved through induced mutagenesis and studies on coffee mutagenesis are scarce. In this chapter, principles and practices of mutation-assisted breeding along with current breeding limitations of Arabica coffee are briefly reviewed, as an introduction to subsequent protocol chapters on mutation induction, advanced cell and tissue culture, Leaf Rust resistance screening and the application of novel molecular/genomics tools supporting mutation-assisted improvement and genetics research of Arabica coffee.