Fusarium seedling blight

Body

Fusrium seedling blight causes a root rot with death of the plant before or after emergence. Symtoms include brown discoloration on roots and coleoptiles of the infected seedlings. Look for brown discoloration on subcrown internodes and on the first two/three internodes of the main stem. 

Images
Image credits
KSU Sorghum Production Problems
Information credit
KSU
Crop type