Search

RATIONALE - New coffee hybrids are important for addressing issues of quality, pests & diseases and climate change, but new plant varieties often encounter slow adoption among farmers due to uncertainties and access. Even when coffee hybrids are shown to be more productive and resistant to (a) biotic stresses, less than 5 % of the orchard in Latin America is planted with hybrids each year. A new dissemination strategy is needed, based on access to technology, data and networks, to increase farmer uptake. This is the aim of the H2020 project BREEDCAFS, based on sharing of propagation techniques locally, local assessment of hybrids in agroforestry systems (AFS), and setup of national stakeholder dialog platforms and sustainable agroforestry clusters. Here, we give a first glimpse of the implementation of this new approach. METHODS - For hybrid assessment, on-farm demo-plots with 4 hybrids and a local control were planted in Nicaragua, Costa Rica, Cameroon and Vietnam. Agronomic observations, quality testing, and farmer surveys are carried out to evaluate productivity, profitability and farmer acceptance. Technology for combined somatic embryogenesis (SE) and rooted mini cuttings (RMC) were transferred to partners in Vietnam, Cameroon and Nicaragua, where dialogue platforms have also been created for all stakeholders in the sector. Further, implementation of agroforestry clusters has been initiated with groups of farmers cultivating new hybrids in sustainable AFS, targeted specialty buyers. RESULTS - The combination of SE and RMC is showing to be a lower-cost approach than solely focusing on the complex and expensive method of SE for vegetative propagation of hybrids. The setting-up of rooted mini cuttings nurseries to Vietnam and Cameroon has allowed mass propagation of hybrids locally at reduced costs, while a women's cooperative in Nicaragua now runs a business producing and selling mini-cuttings. Initial field observations are encouraging; in Costa Rica and Nicaragua hybrids are more productive and produce a better coffee quality in AFS, while observations in Vietnam and Cameroon confirmed higher vigour and yield. In Nicaragua, a 1,250 ha agroforestry cluster is already running successfully, delivering high quality coffee to a specialty buyer; a setup that is now being replicated in Vietnam and Cameroon. CONCLUSIONS and PERSPECTIVES - The hybrids assessed in BREEDCAFS show very promising results. As these hybrids are among the first on the market, many innovations are needed to promote their dissemination and adoption. Our approach to disseminate the Arabica hybrids in the coffee belt form a coherent strategy that appears to be effective in addressing replanting new varieties adapted in the coffee sector.

Conventional American cultivars of coffee are no longer adapted to global warming. Finding highly productive and stable cultivars in different environments without neglecting quality characteristics has become a priority for breeders. In this study, new Arabica F1 hybrids clones were compared to conventional American varieties in seven contrasting environments, for yield, rust incidence and volume of the canopy. The quality was assessed through size, weight of 100 beans, biochemical analysis (24 aroma precursors and 31 volatiles compounds) and sensory analysis. Conventional varieties were the least productive, producing 50% less than the best hybrid. The AMMI model analysis pointed out five hybrids as the most stable and productive. Two F1 hybrids clones, H1-Centroamericano and H16-Mundo Maya, were superior to the most planted American cultivar in Latin and Central America showing a high yield performance and stability performance. H1-Centroamerica and Starmaya contain more d-limonene than Caturra, while Starmaya contain more 3-methylbutanoic acid than the control. Those two latter volatiles compounds are linked with good cup quality in previous studies. In terms of sensory analysis, Starmaya and H1-Centroamericano scored better than control.

Conventional American cultivars of coffee are no longer adapted to global warming. Finding highly productive and stable cultivars in different environments without neglecting quality characteristics has become a priority for breeders. In this study, new Arabica F1 hybrids clones were compared to conventional American varieties in seven contrasting environments, for yield, rust incidence and volume of the canopy. The quality was assessed through size, weight of 100 beans, biochemical analysis (24 aroma precursors and 31 volatiles compounds) and sensory analysis. Conventional varieties were the least productive, producing 50% less than the best hybrid. The AMMI model analysis pointed out five hybrids as the most stable and productive. Two F1 hybrids clones, H1-Centroamericano and H16-Mundo Maya, were superior to the most planted American cultivar in Latin and Central America showing a high yield performance and stability performance. H1-Centroamerica and Starmaya contain more d-limonene than Caturra, while Starmaya contain more 3-methylbutanoic acid than the control. Those two latter volatiles compounds are linked with good cup quality in previous studies. In terms of sensory analysis, Starmaya and H1-Centroamericano scored better than control.

In the present paper, we evaluated the implementation of a seed production system based on the exploitation of male sterility on coffee. We studied specifically the combination between CIR-SM01 and Marsellesa® (a Sarchimor line), which provides a hybrid population called Starmaya. We demonstrated that the establishment of seed garden under natural pollination is possible and produces a sufficient amount of hybrid seeds to be multiplied efficiently and economically. As expected for F1 hybrid, the performances of Starmaya are highly superior to conventional cultivars. However, we observed some heterogeneity on Starmaya cultivar in the field. We confirmed by genetic marker analysis that the off-types were partly related to the heterozygosity of the CIR-SM01 clone and could not be modified. Regarding the level of rust resistance of Starmaya cv., we saw that it could be improved if Marsellesa was more fully fixed genetically. If so, we should be able to decrease significantly the percentage of rust incidence of Starmaya from 15 to 5%, which would be quite acceptable at a commercial level. Starmaya represents the proof of concept for the mass propagation of Arabica F1 hybrid seeds using male sterility. Finally, we discuss the possibility to increase the number of hybrid varieties produced by seed, exploring some initiatives to identify male sterility markers to induce male sterility on any conventional cultivar. This would definitively open up the universe of known Arabica cultivars to be used in breeding new F1 hybrids.

International audience; Since the 1990s, somatic embryogenesis (SE) has enabled the propagation of selected varieties, Arabica F1 hybrid and Robusta clones, originating from the two cultivated coffee species, Coffea arabica and Coffea canephora, respectively. This paper shows how mostly empirical research has led to successful industrial transfers launched in the 2000s in Latin America, Africa, and Asia. Coffee SE can be considered as a model for other woody perennial crops for the following reasons: (i) a high biological efficiency has been demonstrated for propagated varieties at all developmental stages, and (ii) somaclonal variation is understood and mastered thanks to intensive research combining molecular markers and field observations. Coffee SE is also a useful model given the strong economic constraints that are specific to this species. In brief, SE faced four difficulties: (i) the high cost of SE derived plants compared to the cost of seedlings of conventional varieties, (ii) the logistic problems involved in reaching small-scale coffee growers, (iii) the need for certification, and (iv) the lack of solvency among small-scale producers. Nursery activities were professionalized by introducing varietal certification, quality control with regard to horticultural problems and somaclonal variation, and sanitary control for Xylella fastidiosa. In addition, different technology transfers were made to ensure worldwide dissemination of improved F1 Arabica hybrids and Robusta clones. Innovations have been decisive for successful scaling-up and reduction of production costs, such as the development of temporary immersion bioreactors for the mass production of pre-germinated embryos, their direct sowing on horticultural soil, and the propagation of rejuvenated SE plants by rooted mini-cuttings. Today, SE is a powerful tool that is widely used in coffee for biotechnological applications including propagation and genetic transformation. Basic research has recently started taking advantage of optimized SE protocols. Based on -omics methodologies, research aims to decipher the molecular events involved in the key developmental switches of coffee SE. In parallel, a high-throughput screening of active molecules on SE appears to be a promising tool to speed-up the optimization of SE protocols.

International audience; In general, the current industrial somatic embryogenesis (SE) propagation processes for coffee are costlybecause they are not productive enough. We show that SE-derived plantlets from C. arabica hybrids weretemporarily − between 10 and 25 weeks of development in nursery − able to root with a high success rate(up to 90%) whatever the genotype tested, before gradually losing that capacity. We took advantage ofthis transient rooting capacity, probably due to the rejuvenation process occurring during SE, to establisha new propagation system based on the continuous culture of rejuvenated SE plants and on the serialrooting of cuttings under nursery conditions, known as horticultural rooted mini-cutting (HRMC). Theexcessively low SE efficiency with an embryo-to-plantlet conversion rate of only 37% can be greatly offsetby the much higher HRMC multiplication rate (14 in six months) and better overall quality. Fifteen week-old rooted mini-cuttings proved to be more uniform (2–4.5 vs.1–5.5 cm for plant height distribution) andvigorous (1.41 vs. 0.81 mm for stem diameter) than same-age somatic seedlings. This effect persistedfor five years after field planting, mainly through a slightly greater collar diameter (43.3 vs 40.6 mm),whereas at root level no differences were found. The HRMC method is expected to dramatically reducearabica hybrid production costs (by up to 50% at US$ 0.27/plant ready for field planting) and thus topromote the mass utilization of genetically superior hybrid clones of coffee.

Arabica as self-pollinated species is mainly disseminated as homozygous varieties (pure lines) and can be reproduced by seed. Hybrids often present genetic and agronomic advantages: higher and more stable yields, homogeneity, speed of combination of favorable dominant genes in the same genotype. In Arabica, breeding strategies in view of developing F1 hybrid cultivars have been adopted in Ethiopia, East Africa and Central America. In this study, we developed a reproductive and innovative method to produce by seed Arabica F1 hybrids using male sterility.

This work was addressed to assess and optimize the rooting capacity of rejuvenated Coffea arabica F1 plants, derived from somatic embryogenesis (SE). We observed that very young plants can be propagated via rooted cuttings method with very high efficiency (up to 90% of rooting). We strongly believe that the possibility of multiplying somatic embryo-derived plants, through conventional vegetative horticultural mini-cuttings, would offer new perspectives to guarantee the profitability of the high scale micro-propagation business and hence will bring the interest of private sector.