Review Ecophysiological constraints on the production of shaded and unshaded coffee: a review Fa ´bio M. DaMatta * Departamento de Biologia Vegetal, Universidade Federal de Vic ¸osa, 36571-000 Vic¸osa, MG, Brazil Received 21 May 2003; received in revised form 27 August 2003; accepted 2 September 2003 This review is dedicated to Dr. M. Antonieta Nunes (IICT, Portugal) on the occasion of her retirement Abstract The ecophysiological constraints on the production of the arabica and robusta coffee under shading or full sunlight are reviewed. These two species, which account for almost all the world’s production, were originally considered shade-obligatory, although unshaded plantations may out-yield shaded ones. As a rule, the benefits of shading increase as the environment becomes less favorable for coffee cultivation. Biennial production and branch die-back, which are strongly decreased under shading, are discussed. The relationships between gas exchange performance and key environmental factors are emphasized. Ecophysiological aspects of high density plantings are also examined. # 2003 Elsevier B.V. All rights reserved. Keywords: Coffea; Environmental factors; Gas exchange; High density planting; Photosynthesis; Shading 1. Introduction Coffee is the most important commodity in the international agricultural trade, representing a signi- ficant source of income to several Latin American, African and Asian countries. In 2000/2001, coffee was planted on some 11 million ha, yielding 115 million bags (60 kg) of green coffee beans, of which Coffea arabica L. (arabica coffee) accounted for 63%, and C. canephora Pierre (robusta coffee) the remainder of the coffee produced. This paper reviews the produc- tion of shaded and unshaded coffee of these two species. Coffee is native to tropical Africa where it is believed to have evolved as an understorey tree. Early plantations were shaded by planting overstorey trees to simulate the natural habitat. In many situa- tions, however, coffee grows well without shade and even out-yields shaded coffee (Fournier, 1988; Beer et al., 1998). Shading was therefore abandoned as a regular cultural practice in several regions. In Brazil, the world’s largest coffee producer, the practice was almost completely abandoned in 1950s (Malavolta, 2000). The question of whether the coffee tree benefits or not from shelter trees has been disputed for more than a century (Lock, 1888; Mayne, 1966; Gopal et al., 1970; Fournier, 1988; Muschler, 1997; Beer et al., 1998; DaMatta and Rena, 2002). Yield potential, competition for water and nutrients, and pest/disease incidence are central issues in this controversy (Beer et al., 1998). Unshaded plantations generally require high levels of external inputs to maximize crop yield Field Crops Research 86 (2004) 99–114 * Fax: þ55-31-3899-2580. E-mail address: fdamatta@ufv.br (F.M. DaMatta). 0378-4290/$ – see front matter # 2003 Elsevier B.V. All rights reserved. doi:10.1016/j.fcr.2003.09.001