Breeding for the Main Agricultural Farming of Arabica Coffee

Abstract

So far, the main Arabica coffee breeding programmes in Latin America have focused on the selection of varieties adapted to intensive full-sun farming systems. Meanwhile, little attention has been paid to breeding varieties specifically adapted to shade, which is the main characteristic of agroforestry systems (AFS). Yet the specialty coffee sector is currently expanding and seeking specific sensory qualities related to exotic varieties and no breeding programme exists to create new varieties for this type of market. Two trials were set up: one in full sun and the other under shade. F1 hybrids and their parents (pure lines and Ethiopian accessions) were studied in a factorial-crossing design to measure tree volume, yield (3 years), bean size, the bean NIRS signature and the final cupping score. Bean size and the final cupping score seemed to be relatively unaffected by shading. Strong maternal heritability was observed for bean size. In the trials, F1 hybrids produced “75–80%” more than the maternal lines and “40–50%” more than the male parents in the shade trial and in the full-sun trial, respectively. By choosing the F1 hybrid, it is possible to increase productivity under both shade and full sun while simultaneously achieving good sensory qualities. Selecting a F1 hybrid for “specialty coffee” seems exceptional. This raises a fundamental issue concerning the maternal heritability of seed biochemical composition. We conclude that selection under shade is essential for the selection of varieties adapted to AFS.

Alternative plant protection strategies for tomorrow's coffee

“…Plant protection of food crops is precarious and temperature‐dependent infection risks are predicted to put increasing pressure on farmers globally in the coming years (Chaloner et al, 2021). While new coffee hybrids and cultivars are being continuously bred for improved traits such as pest and disease resistance (Bertrand et al, 2021), farmer adoption has historically been low due to the perennial nature of the crop, price and other cultural preferences (Meressa & Navrud, 2020; Turreira‐García, 2022). Given this, NGT for coffee cultivation challenges must accommodate the long production cycles as well as low economic resources of the coffee farmer.…”

“…However, the artificial shade net does not simulate all field dynamics that are inherent to AFS, thus more contemporary studies are making use of natural shaded coffee systems to resemble AFS, such as fast‐growing banana plants as a shade source (Figure 1b). Recent studies and meta‐analyses are also showing gene × environment (G × E) interactions, which indicate that some coffee cultivars are higher yielding compared to others under shade (Bertrand et al, 2021; Koutouleas, Sarzynski, Bertrand, et al, 2022; Piato et al, 2020). The often full‐sun cultivated Coffea canephora showed significant intraspecies differences in yield when grown under moderate to high shade environments (41%–65%) (Piato et al, 2020).…”

Shaded-Coffee: A Nature-Based Strategy for Coffee Production Under Climate Change? A Review

“…Breeding efforts have also traditionally focused on plant vigor and productivity (van der Vossen et al, 2015). However, the recent implementation of new agricultural policies, both public and private, and breeding efforts turned their attention to shaded coffee and intercropping systems, often as an adaptation strategy to climate change or as part of a certification process (Rice, 2018;Vanderhaegen et al, 2018;Bertrand et al, 2021). Recent efforts, notably public programs in Vietnam and China, have pushed for the conversion of large areas of full sun coffee into shaded systems (Rigal et al, 2018) and for the introduction of fruit trees intercropped with coffee trees (Thuy et al, 2019).…”

“…Unlike Arabica coffee, breeding programs geared toward C. canephora coffee currently do not select for shaded cultivation systems (Carvalho et al, 2019;Alkimim et al, 2021). Moreover, selection criteria for AFS were not clearly established until Bertrand et al (2021) proposed a list of target traits including productivity, size of the beans, sensory score, and coffee tree volume allowing a high number of trees per hectare. Applying these criteria, they found hybrids capable of producing up to 22% more than the best pure line under full sun.…”

Shade effects on yield across different Coffea arabica cultivars — how much is too much? A meta-analysis

“…Despite this, coffee is known to have a high degree of phenotypic plasticity to environmental variations (Kufa & Burkhardt, 2011a, b;Tounekti et al, 2018;DaMatta et al, 2019), although cultivar performances can vary greatly depending on the given cultivation site (Matos et al, 2009). Moreover, current coffee breeding programs utilising wild and cultivated crosses are, in some cases, demonstrating hybrid superiority (colloquially described as "hybrid vigour" and also referred to as "heterosis") in new Arabica cultivars when evaluated across different environments (Bertrand et al, 2019(Bertrand et al, , 2021Georget et al, 2019;Marie et al, 2020;Pappo et al, 2021).…”