Master of Science
Date of Defense
Many critical agronomic traits have been selected over the course of domestication of various crops and of these, one of the most crucial for cereal crops (Poaceae) is increased seed retention or “reduced shattering”, although the underlying mechanisms remain poorly understood. Setaria viridis was selected to identify the underlying patterns related to abscission zone development within the previously uncharacterized tribe Paniceae (Panicoideae). For this study one line of the wild species S. viridis and two lines of S. italica , a derived domesticate of S. viridis , were used. Consistent differences were found in the phenotypic patterns and morphology of S. viridis abscission layers compared to either S. italica accession. In addition, the abscission zone itself forms completely only in S. viridis whereas the analogous region in S. italica is poorly formed or absent. Among the currently known shattering genes, qSH1 and SH1 were expressed in both S. viridis and S. italica during flowering. It seems likely that the mechanism for abscission in Setaria is morphologically distinct from the shattering mechanisms seen in other grasses although they may all utilize similar underlying pathways.
Hodge, John Gerard, "Morphology and Characterization of Abscission Zone Development and its Role in Domestication in Setaria viridis and Setaria italica" (2015). Theses. 37.