Use of adapted strains of red clover is highly important in getting top yields of forage and seed. Here's why along with a brief description of some of the more promising improved varieties.
Wilsie, C. P.
"Clover Varieties for Iowa,"
Iowa Farm Science: Vol. 5
, Article 6.
Available at: https://lib.dr.iastate.edu/farmscience/vol5/iss12/6