136 SOUTHERN FIELD CROPS 



The multiplication-plot. — The ears from the most productive 

 rows inherit productiveness on the side of the female or pistillate 

 parent ; but the pollen that fertilized these ears may have come 

 from one of the most inferior rows. In order to insure the best 

 pollen, careful plant-breeders sometimes take the additional step 

 of planting each year a special multiplication-plot, or mating 

 area of corn. 



In this they plant the remnants of the best original ears saved 

 from the planting of the preceding spring. These original 

 ears in the intervening year have shown their ability to transmit 

 productiveness to their offspring. These remnants of ears are 

 pure ; that is, free from admixture of pollen from inferior strains. 



Hence, most rapid progress in corn breeding is made by having 

 in the second year an isolated multiplication or mating-plot, 

 in which are planted in alternate rows two or more of the best 

 remnants of ears, as judged by the yields of the offspring of parts 

 of the same ears in the ear-to-row test. 



Half of the rows in the multiplication-plot should be detasseled. 

 Thus self-fertilization is avoided and the union by oross-fertUiza- 

 tion of two productive strains is insured. 



When it is feasible to plant such a mating-patch, the ears 

 from its detasseled rows constitute the seed for a seed patch of the 

 third year, the product of which wiU plant the entire general crop 

 of the farm, or be sold for seed. Since special equipment of venti- 

 lated, insect-proof jars or cases is needed in the South to preserve 

 the remnants of the original ears for one year, most breeders omit 

 the mating-plot, planted with such remnants of ears. 



122. Breeding for . composition. — Hopkins and Smith, 

 at the Illinois Experiment Station (Bui. Nos. 119 and 128), 

 have proved that the composition of corn can be varied 

 by selection of seed-ears. They selected for many years 

 in succession kernels rich in the chemical constituent 

 desired, as fat, protein, or starch. After continuing this 

 work for a number of years, great variations were found in 

 the resulting strains. For example, after ten years of 



