A review of tef physiology for developing a tef crop model

Tef (Eragrostis tef (Zucc.) Trotter) is important for Ethiopian food security and a significant source of income for smallholder farmers in Ethiopia. In industrialized nations, tef is becoming a popular health food due to its lack of gluten and high nutritional value. Though tef is an important crop within Ethiopia, research on the crop has been limited. Crop models are an important tool for assessing food security, the effectiveness of management practices, and the impacts of climate change on crop production. The only existing crop models for tef are the FAO-AEZ crop growth simulation model, and the FAO AquaCrop model, which focuses on water limited crop production. The FAO AEZ model only produces final yields, which limits its applicability. The AquaCrop model has been validated using data from northern Ethiopia under current climate conditions without nitrogen limitations. As tef production spreads across the world, and Ethiopia suffers from soil fertility depletion and climate change, there is a need for a more comprehensive tef model. Tef, a short-day C4 crop, shows a high level of genetic diversity, resulting in large variation in water use, water use efficiency, growing season length, and even photosynthetic rate across cultivars. Tef quickly reaches a closed canopy, resulting in a higher early-season water use efficiency than wheat (C3 crop) or sorghum (C4 crop). Lodging is a significant yield limitation in tef, and is often exacerbated by fertilizer applications. There are several areas of tef research that have limited, or no, published data, especially on a field level, which will hinder future tef model development. These areas include the effects of temperature on photosynthesis and phenology, the effects of heat stress on senescence, the effects of elevated atmospheric CO₂ on photosynthesis and transpiration, and a field level lodging model. By combining relevant information from other crops with the available tef literature, however, it should be possible to create a tef crop model prototype.