The cocoa crop growth is highly influenced by environmental conditions, viz. temperature, which influence the phenological stages of flowering, fruiting, and pod growth. The plant produces caulescent flowers that are hermaphrodite and pollinated by insects, mainly Forcipomyia sp. (Diptera: Ceratopogonidae), but flowers setting to pods are very low. The efficiency of pollination depends on the degree of pollen compatibility and the number of pollen grains deposited on the stigma. It is assumed that midge population can be a limiting factor in the pollination of cocoa in addition to the environmental conditions. However, populations of insect pollinators are often severely disturbed by hurricanes through flooding of essential habitat and the widespread loss of existing flowers. This chapter will explore the role of midges [biotic] and the effect of climate [abiotic] variables. Understanding these ecological dynamics can lead to ways of conserving midge populations, mitigating the effects of global climate change and extreme climatic events. 2 1.1 Cacao stress Cacao cultivation is challenged by multiple abiotic and biotic stress factors [5], as they sessile to physical environment interactions with pest and pathogens [6], evapotranspiration [7], soil salinization [8], and climate change [9]. They developed a multitude of defence mechanisms to adapt and survive stress conditions [10] and harmful microorganisms [11].
Cacao agroecologyThe agroecological zones [AEZ] relate to soil fertility cycling and weed, pest, and watershed management. The cacao crop growth is specific to the AEZ, viz. temperature [12], flooding [13], and water stress [14]. The bimodal seasons influence the phenological stages of flowering, fruiting, and pod growth [15]. Water stress inhibits leaf development and pod setting and induces leaf abscission and photosynthetic rate (PR) [16].
Scope of stress pollination and fertilizationThe ecophysiology of abiotic and biotic stress on the pollination and fertilization of cacao is specific to four (4) main stages in the crop reproductive cycle, viz. prepollination, pollination fertilization, and postfertilization. This treatise processes from pollen germination to ovary fusion to the young pod development or cherelle [4].The scope of the treatise is limited to the author's research and critical review of the biotic or the internal factors that influence flower and fruit set in cacao. The abiotic factors are light intensity, relative humidity (RH), flooding, water stress, and cultural practices as shade, intercropping, and crop nutrition. The resilience of the pollinator to adapt to climatic changes and crop residue manipulation to increase the population dynamics of the cacao midges is examined, as well as advances in the area of olfactory sensitivity and cacao pollen odour [17].
Botany
Vegetative stageCacao can be propagated by seedling, cuttings, or terminal grafts, reach maturity at 12-18 months [4], and develop juvenile vertical shoot which produces lateral branches or "jorquette/chupons". It is an ...