Unraveling the central role of root morphology and anatomy in lodging of tef (Eragrostis tef)

Societal Impact Statement: Crop diversification is considered key to ensuring agricultural sustainability and food security. Tef (Eragrostis tef (Zucc.) Trotter) is a cereal crop grown mainly in Ethiopia, where it thrives in a wide range of environments, including stress-prone habitats. It is considered a promising new crop and is gaining popularity in cultivation and in research worldwide. Lodging, the greatest factor limiting tef productivity and its wide adoption, was targeted in this study. The results highlight the central role of root traits in tef lodging, thus paving the way to reducing lodging and improving tef productivity, crop diversification, and food security. Summary: Lodging is the most prominent yield-restricting problem in tef (Eragrostis tef (Zucc.) Trotter) cultivation, responsible for 30%–50% yield loss. A significant advance in lodging resistance has been achieved in various cereals by reducing plant height. In this study, we investigated the role of crown root morphology and anatomy, rather than plant height, in tef lodging. Twenty-eight tef lines, representing a wide diversity in lodging tendencies and major phenotypic traits, were tested under two field environments to investigate tef lodging and related traits. Four selected lines were subjected to more intense sampling as well as anatomical analysis of crown roots. In both field studies, taller lines were associated with greater lodging shortly before flowering, but not at plant maturity, whereas crown root diameter exhibited an association with reduced lodging, which became highly significant at maturity. Moreover, a greater proportion of root cortical aerenchyma developed in lodging-susceptible genotypes, possibly reducing plant anchorage. A positive association between grain yield and lodging presents a major challenge for tef breeding. Our results suggest that root traits play a central role in tef lodging responses. We propose that semi-dwarfism should be complemented by targeting root traits, to promote lodging resistance in tef.