The physiological responses of cacao to the environment and the implications for climate change resilience. A review

Abstract

Cacao (Theobroma cacao L.) is a tropical perennial crop which is of great economic importance to the confectionary industry and to the economies of many countries of the humid tropics where it is grown. Some recent studies have suggested that climate change could severely impact cacao production in West Africa. It is essential to incorporate our understanding of the physiology and genetic variation within cacao germplasm when discussing the implications of climate change on cacao productivity and developing strategies for climate resilience in cacao production. Here, we review the current research on the physiological responses of cacao to various climate factors. Our main findings are as follows: (1) water limitation causes significant yield reduction in cacao, but genotypic variation in sensitivity is evident; (2) in the field, cacao experiences higher temperatures than is often reported in the literature; (3) the complexity of the cacao/shade tree interaction can lead to contradictory results; (4) elevated CO 2 may alleviate some negative effects of climate change; (5) implementation of mitigation strategies can help reduce environmental stress; and (6) significant gaps in the research need addressing to accelerate the development of climate resilience. Harnessing the significant genetic variation apparent within cacao germplasm is essential to develop modern varieties capable of high yields in non-optimal conditions. Mitigation strategies will also be essential, but to use shading to best effect shade tree selection is crucial to avoid resource competition. Cacao is often described as being sensitive to climate change, but genetic variation, adaptive responses, appropriate mitigation strategies and interactive climate effects should all be considered when predicting the future of cacao production. Incorporating these physiological responses to various environmental conditions and developing a deeper understanding of the processes underlying these responses will help to accelerate the development of a more resource use efficient tree ensuring sustainable production into the future.

Environment and pathogens shape local and regional adaptations to climate change in the chocolate tree, Theobroma cacao L.

“…Yet, further work is needed to better characterize the sensitivity to drought across populations and among individuals within populations in T. cacao . Although it is generally found that T. cacao is sensitive to drought (Lahive et al, 2019), there is limited information about the variability in drought susceptibility across populations (Atayese et al, 2012), making it difficult to further characterize how these SNPs contribute to drought tolerance.…”

Perceived Climate Resilience and Adoption of Cocoa Agroforestry in the Forest-Savannah Transition Zone of Ghana

“…Although the drought disadvantage of cocoa agroforestry was perceived by a limited proportion of household heads, it is somehow supported by more recent studies [7,43,49]. For instance, Abdulai et al [43] found in the FSTZ of Ghana that cocoa plants under Albizia ferruginea and Antiaris toxicaria suffered 100% and 77% mortality respectively during the 2015/16 drought, while cocoa in full sun, suffered only 12% mortality [50].…”

“…Agroforestry (the integration of shade trees) has received considerable attention in the literature as an effective climate-resilient strategy in cocoa production [7,8,9]. Nevertheless, cocoa agroforestry adoption is low [10,8] as farmers increasingly switch to full-sun monoculture [10,9,11].…”

The Role of Fungi in the Cocoa Production Chain and the Challenge of Climate Change

“…The extreme changes might shape crops and ultimately the yield of cocoa. In a very interesting review, Lahive et al [ 145 ] considered the current research on cocoa’s physiological responses to CC. In the present paper, we consider the influence of CC on cocoa mycobiota during the different production steps because it is possible that new interactions of the fungi may affect the cocoa production chain and the final product’s quality ( Figure 3 ).…”