Hot Coffee: The Identity, Climate Profiles, Agronomy, and Beverage Characteristics of Coffea racemosa and C. zanguebariae

Abstract

Climate change poses a considerable challenge for coffee farming, due to increasing temperatures, worsening weather perturbations, and shifts in the quantity and timing of precipitation. Of the actions required for ensuring climate resilience for coffee, changing the crop itself is paramount, and this may have to include using alternative coffee crop species. In this study we use a multidisciplinary approach to elucidate the identity, distribution, and attributes, of two minor coffee crop species from East Africa: Coffea racemosa and C. zanguebariae. Using DNA sequencing and morphology, we elucidate their phylogenetic relationships and confirm that they represent two distinct but closely related species. Climate profiling is used to understand their basic climatic requirements, which are compared to those of Arabica (C. arabica) and robusta (C. canephora) coffee. Basic agronomic data (including yield) and sensory information are provided and evaluated. Coffea racemosa and C. zanguebariae possess useful traits for coffee crop plant development, particularly heat tolerance, low precipitation requirement, high precipitation seasonality (dry season tolerance) and rapid fruit development (c. 4 months flowering to mature fruit). These attributes would be best accessed via breeding programs, although these species also have niche-market potential, particularly after further pre-farm selection and post-harvest optimization.

Ethnopharmacological study of the genus Coffea and compounds of biological importance

“…This species is very similar to C. liberica, and it is rarely found in markets, although its beans are very aromatic (Clifford & Willson, 1985;Herrera & Lambot, 2017). C. racemosa is a lesser known species; it is cultivated in Mozambique and in northern South Africa; the caffeine content of C. racemosa is lower than that of C. arabica, and it is characterized by a bitter taste, highlighting the flavors of mint and wood (Davis et al, 2021). The species C. stenophylla is found in West Africa, where it is endemic to the Comoros Archipelago, and is characterized by a mild flavor similar to that of Arabica coffee.…”

“…Crosses of C. racemosa with Arabian varieties have been reported, generating hybrids such as C. aramosa, with resistance to L. coffeella and drought and low caffeine content. Similarly, hybrids have been obtained from a cross between C. canephora and C. congensis with drought tolerance (Barrera, 2017;Davis et al, 2021). The species C. liberica and C. excelsa express greater resistance than other species to H. hampei because their fruits have a thicker pericarp that hinders the entry of microorganism; although no hybrid species have been reported in the market with resistance to this insect, these coffee species could be an alternative to meet the demands of farmers (Barrera, 2017).…”

Potential beverage quality of three wild coffee species (Coffea brevipes, C. congensis and C. stenophylla) and consideration of their agronomic use

“…8 Its cup profile is similar to C. racemosa but has a larger bean (seed size) and higher yield. 8 In order to conserve at least part of the genetic diversity of wild coffee species, ex situ coffee collections are located in several countries. 15 The Coffea Biological Resources Center (BRC Coffea), maintained on Reunion Island, is the result of numerous prospecting and campaigns in Africa (Cameroon, Ivory Coast, Ethiopia, Guinea, Kenya, Central African Republic (CAR), Republic of Congo, Tanzania), with the participation or support of national agronomy research centres and international institutions over a period from the 1960s to the 1980s.…”

“…Coffea racemosa is a species native to Mozambique, Zimbabwe and South Africa. 8,9 Hallé and Faria, 12 cited by Guerreiro Filho, 13 observed the existence of small-scale cultivation of C. racemosa in Mozambique for local consumption. It is now being cultivated at small scale in South Africa (https://www.racemosa.coffee/).…”

A review of the indigenous coffee resources of Uganda and their potential for coffee sector sustainability and development

“…Examples include the use of wild material for: coffee berry disease (CBD; Colletotrichum kahawae J.M.Walter & Bridge) resistance for Ethiopian C. arabica (Yonas et al, 2014); coffee wilt disease (CWD; Gibberella xylarioides R. Heim & Sacca) resistance for Ugandan C. canephora (Kiwuka et al, 2021;Mulindwa et al, 2022); coffee leaf rust (CLR; Hemileia vastatrix Berk. & Broome) resistance, globally, for C. arabica, through crossing with C. canephora (Clarindo et al, 2013;Avelino et al, 2015) and C. liberica (Narasimhaswamy, 1960;Surya Prakash et al, 2002); and coffee leaf miner (Perileucoptera coffeella Meńeville) resistance (Medina Filho et al, 1977a;Medina Filho et al, 1977b) and drought tolerance (Grisi et al, 2008;Melo et al, 2014;Carvalho et al, 2017) in C. arabica, through crossing with C. racemosa (Davis et al, 2021a). It is worth noting that wild species were used to sustain the global coffee industry in response to the devasting influence of CLR at the end of nineteenth century, firstly using C. liberica, from c. 1875-1900, and then C. canephora from the early 1900s onwards (McCook, 2014;Davis et al, 2019;McCook, 2019;Davis et al, 2022).…”