Sorghum is a grain similar to corn that is grown in areas where it is too hot and too dry to grow corn. In the US, sorghum is grown throughout Texas to South Dakota and is used as feed grain for livestock. However, like other plants, sorghum suffers from root rot if exposed to poorly drained and cold soil.
Root rot in sorghum causes the grain to grow smaller than it should by stunting its growth. Standard modern sorghum is 2 to 4 feet tall. Sorghum that is much smaller than this might have a root rot problem.
Sorghum root rot causes the normally green leaves of the sorghum to turn yellow or brown, in some cases. It may also cause the leaves of the sorghum plant to wilt even when they are being watered properly.
Sorghum root rot is caused by a common fungi found in most soils. It will not rot the sorghum's roots unless the plant is stressed. If the plant does succumb to the disease the sorghum's roots will turn pink, reddish-brown or black due to the infection. To check the color of the sorghum's roots you'll have to dig up the plant and look at them.