Diversity, Combining Ability And Coffee Berry Disease (Colletotrichum Kahawae) Resistance Among Ethiopian And Tanzanian Arabica Coffee Genotypes

 ABSTRACT

Background Coffee is the most important stimulant beverage in the world and a major form of cash income for millions of smallholder farmers. The world’s coffee trade is dominated by two types Arabica and Robusta. Arabica represents 60-70% whereas Robusta represents 30-40% of global exports. Coffee is one of Tanzania’s primary agricultural export commodities accounting for about 5% of total exports value, and generating export earnings averaging USD 100 million per annum over 30 years by 2012. Insufficient information of genetic diversity at molecular level of germplasms and breeding materials existing in the Institute, absence of fast, convenient and high precision screening tools/diagnostic markers for coffee berry diseases (CBD) resistance, narrow genetic base of released improved coffee varieties and little knowledge base of genetics of arabica coffee traits leads to low efficiency in development and release of improved superior arabica coffee varieties in a reduced time. The main objective of this study was to generate information, which will be used to address the above problems. The specific objectives were: to determine the genetic diversity of Tanzanian coffee germplasm and the Ethiopian Coffea arabica collection maintained in Tanzania using simple sequence repeats (SSRs) molecular markers; to incorporate coffee berry disease resistance and screen progenies of the crosses between Ethiopian accessions and Tanzanian commercial variety KP423 for Coffee Berry Disease (CBD) resistance genes using SSR markers; to determine the combining ability, heritability and relationships of growth and yield characters of progenies of commercial variety KP423 and selected accessions of Ethiopian collection.