PLANT BREEDING 181 
8. The’ varieties distinguished by such characters as are 
mentioned in the preceding paragraph often differ much in 
their economic value, which depends on such qualities as pro- 
ductiveness, resistance to drought, resistance to rust, and the 
grade of flour which they produce. 
4, Varieties usually come true from the seed, so that, when 
one has been chosen and isolated, it may be grown indefinitely 
with little change. 
172. Variation in corn. Indian corn is preéminently an 
American plant. At the time of the discovery of America, 
ath Vaan ATL RIY 
pahatt eA aa 
Se OOGAU DOO NLENSCCCSUFUES GTI COUISER'® 
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APA Ug da hd 
Fic. 156. A prize ear of Johnson County White corn? 
An admirable type of dent corn. Photograph by L. B. Clore 
and probably for a long period before that time, it was grown 
by the Peruvians, by the Mexicans, and by many tribes of 
Indians. It is supposed to have originated in South America 
or Central America, near the west coast. Varieties of corn 
differ greatly in size (from 1} to 22 feet high) and in the 
time required for maturing. Some corn in Paraguay is said 
to ripen in one month, while Illinois field corn requires from 
four to five months.” 
1 This ear of corn was bid in by the grower (Mr. Clore) at an auction sale 
of exhibits at the Chicago National Corn Exposition in October, 1907. The 
price paid was $250. 
2 See Bulletin 57, Office of Experiment Stations, U.S. Dept. Agr., 1899, 
