SWEET CORN 
Since 1884, Northrup King has been actively engaged in research and production of 
sweet corn. All NK sweet corn has been grown under the direction of our own trained 
personnel. 
The same principles of breeding that have made Kingscrost hybrid field corn what 
it is today have been applied to sweet corn. As a result of this work, sweet corn hybrids 
have replaced most of the older open pollinated varieties. 
This method of corn breeding involves the development of pure lines or strains 
(inbreds) by years of inbreeding and careful selection. The process requires at least five 
years to develop each inbred parent. During the inbreeding work, countless undesirable 
plants are discarded for each one selected and perpetuated. Vigor and size are necessarily 
sacrified for purity and uniformity. Then, after two selected compatible inbreds are 
crossed, hybrid vigor results and the single cross hybrid is superior in every respect to 
the corn from which the inbred parents originated. These points of superiority are 
increased yield, more vigorous growth, disease resistance, greater plant and ear uni- 
-formity as well as better quality. 
Seed should not be saved from corn planted with hybrid seed because there is a 
genetic break-up with definite loss in vigor and uniformity as compared with the first 
generation hybrid seed. A true hybrid variety must be newly crossed for each seed crop 
with carefully maintained pure parent lines. This is done by alternate planting of the 
inbred parents, through detasseling of the female rows, careful rogueing and proper 
isolation from other varieties. 
Northrup, King & Co. started inbreeding sweet corn in 1922, and were one of the 
first to institute such an intensive breeding program. Today our sweet corn breeding 
and trial grounds are among the largest in the country. Modern principles and techniques 
are used to originate new and better hybrids for all classes of trade. 
Maturity dates are from emergence to canning or eating stage. 
A Northrup, King & Co. Hybrid Sweet Corn Production Field 
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