Coffee is an important crop that provides a livelihood to millions of people living in developing countries. Production of genotypes with improved coffee quality attributes is a primary target of coffee genetic improvement programs. Advances in genomics are providing new tools for analysis of coffee quality at the molecular level. The recent report of a genomic sequence for robusta coffee, Coffea canephora, is a major development. However, a reference genome sequence for the genetically more complex arabica coffee (C. arabica) will also be required to fully define the molecular determinants controlling quality in coffee produced from this high quality coffee species. Genes responsible for control of the levels of the major biochemical components in the coffee bean that are known to be important in determining coffee quality can now be identified by association analysis. However, the narrow genetic base of arabica coffee suggests that genomics analysis of the wild relatives of coffee (Coffea spp.) may be required to find the phenotypic diversity required for effective association genetic analysis. The genomic resources available for the study of coffee quality are described and the potential for the application of next generation sequencing and association genetic analysis to advance coffee quality research are explored.Key words: Coffee quality, genetics, genomics, biochemical compounds, next generation sequencing, association studies.This article is protected by copyright. All rights reserved.
Accepted Article
GENERAL INTRODUCTIONCoffee is an important crop and the second most traded commodity in the world (after petroleum) providing a living to more than 125 million people .Commercial coffee production is dominated by only two species belonging to the Coffea genus: C. arabica and C. canephora (the latter generally referred to as robusta coffee). All coffee species are diploid (2n=2x=22) and generally self-incompatible, except for C. arabica which is a self-fertile tetraploid (2n=4x=44) derived from a spontaneous hybridization between C. canephora (as paternal progenitor) and C.eugenioides (as maternal progenitor) 8 9.Although C. arabica is considered to have better cupping quality than C. canephora, improving the quality of both commercial species remains a target for most coffee improvement programs. With advances in genomic and sequencing technology, it is feasible to understand the coffee genome and the molecular inheritance underlying coffee quality, thereby helping improve the efficiency of breeding programs.This review will discuss current knowledge regarding the genetics of those biochemical compounds which are considered quality determinants, for use as a foundation for improving coffee quality by breeding. Available genomic resources for the study of the genetics of biochemical compounds that are likely to be playing a role in coffee flavour will also be discussed. In addition, the potential value of the study of genetics of coffee This article is protected by copyright. All rights reserved.Ac...