Introduction

Coffea arabica & Coffea canephora  

Coffee sustains over 100 million people globally and is rated among the largest export
commodities in the world. Coffea arabica (arabica or highland coffee) and Coffea canephora
(Robusta or lowland coffee) are the main coffee species that are commercially grown, however there are 124 coffee species existing and which have been named to date. Coffee Arabica contributes 70% of produced coffee while Robusta contributes 30% (ICO, 2016).
In Kenya, coffee was first planted in 1893 at Bura in Taita hills thereafter it was grown in Kibwezi in 1900 followed by Kiambu in 1904, since then coffee growing was expanded to several areas of Central Kenya, Meru, Kisii, Machakos, Mount Elgon and Rift Valley.