NORTHRUP, KING & CO’S KINGSCROST HYBRID SEED CORN 
Northrup, King & Co. was one of the first of the seedsmen to begin 
developing hybrids through inbreeding. 
In 1922 we started by inbreeding 1,000 selected plants of Minn. No. 13. 
Each year since then from 50,000 to 100,000 inbred plants have been 
grown in the development of our inbred strains. 
Starting in 1928, experimental crosses were made and tested for 
yield. Approximately 1,000 to 2,000 yield comparisons have been made 
each year since. 
In 1931, small quantities of our first double crosses were grown for 
seed. These were widely distributed for trial with farmers. 
By 1933, hybrid seed corn production had become a factor and now 
several thousands of acres of hybrid seed corn are being produced to sell 
under the Kingscrost Brand. 
One of the trial grounds of Kingscrost and Sterling Seed Corn operated in eastern Wisconsin. Here 
farmers could check on the relative merits of each strain. 
Inbreeding plot showing method of “bagging” the tassels so hand pollination can be done effectively. 
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