Starmaya: The First Arabica F1 Coffee Hybrid Produced Using Genetic Male Sterility.

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.

Coffee Somatic Embryogenesis: How Did Research, Experience Gained and Innovations Promote the Commercial Propagation of Elite Clones From the Two Cultivated Species?

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.

Coffee (Coffea sp.).

Coffee (Coffea sp.) is a perennial plant widely cultivated in many tropical countries. It is a cash crop for millions of small farmers in these areas. As compared with other tree species, coffee has long breeding cycles that make conventional breeding programs time consuming. For that matter, genetic transformation can be an effective technique to introduce a desired trait in an already "elite" variety, or to study a gene function and expression. In this chapter, we describe two Agrobacterium-mediated transformation techniques; the first with A. tumefaciens to introduce an insect resistance gene and the second with A. rhizogenes to study candidate gene expression for nematode resistance in transformed roots.

Comparison of bean biochemical composition and beverage quality of Arabica hybrids involving Sudanese-Ethiopian origins with traditional varieties at various elevations in Central America.

For buyers of Arabica coffee (Coffea arabica L.) in Central America, elevation and variety are important indicators of quality. We compared coffee produced by three types of varieties established in various trials at elevations ranging from 700-1600 m in three countries (El Salvador, Costa Rica and Honduras). Arabica hybrids resulting from crosses of Sudanese-Ethiopian origins with either traditional varieties or with introgressed lines derived from the hybrid of Timor (C. arabica x Coffea canephora Pierre ex Froehn) were compared with traditional cultivars (TC). Effects of elevation and variety on bean biochemical composition (caffeine, chlorogenic acid, trigonelline, fat and sucrose) were evaluated by predictive models based on calibration of near-infrared (NIR) spectra and by chemometric analysis of the global NIR spectrum. Beverage quality tests were performed by a panel of ten professional cup-tasters. Experiment 1 was carried out on the slopes of the Poas volcano (Costa Rica) with the traditional cultivar 'Caturra'. Experiment 2 compared the three varieties in a network of trials established in three countries of Central America. Significant linear regressions with elevation were observed in Experiment 1 with Caturra and in Experiment 2 for the traditional cultivars, and trends were established relating variation in biochemical compounds and cup quality to elevation. Convergence or divergence of the new hybrids in relation to these trends was observed. For the traditional cultivars, elevation had a significant effect on bean biochemical composition, with chlorogenic acid and fat concentrations increasing with increasing elevation. For the Arabica hybrids, elevation explained little of the variation in chlorogenic acid concentration and none of the variation in fat concentration. Nevertheless, Arabica hybrids had 10-20% higher fat concentrations than the traditional varieties at low elevations and similar fat concentrations at high elevations. The samples could be discriminated according to elevation based on NIR spectra; however, the spectra of the TC varieties were more strongly modified by elevation than the spectra of the hybrids. Nonetheless, this analysis confirmed homeostasis of the hybrids for which bean biochemical composition was less affected by elevation than that of the traditional varieties. The organoleptic evaluation, performed on samples originating from high elevations, showed no significant differences between Arabica hybrids and traditional cultivars. The new hybrid varieties with high beverage quality and productivity potential should act as a catalyst in increasing the economic viability of coffee agroforestry systems being developed in Central America.