CHAPTER XIV 

 MAIZE BREEDING 



Maize was the most important bread crop of the American In- 

 dians and even today is the most important crop in the western 

 hemisphere. The Indians brought the culture of maize to a 

 high state of advancement and developed innumerable varieties. 

 On the foundations made by the Indians modern corn-breeding 

 has made marked advances, but perhaps no North American 

 varieties are so notable as those developed by the Incas in Peru. 



Origin and Species. It is generally believed that Mexico is the 

 original home of the maize plant, although there is no absolute 

 proof of this (Harshberger, 1897). Zea mays L., belongs to the 

 tribe Maydeae of the order Gramineae. All varieties of Indian 

 corn are placed in the species mays. The nearest relative of 

 maize is teosinte, EucMcena mexicana Schrad. Teosinte and 

 maize cross readily and a natural hybrid between these cultivated 

 grasses was described under the name Zea canina by Watson 

 (Harshberger, 1904). A study of these crosses led Harshberger 

 (1904, 1909) to make the hypothesis that maize originated from a 

 hybrid between a sport of Euchlsena and normal teosinte. Mont- 

 gomery (1906) reached the conclusion that maize and teosinte 

 had a common progenitor. It was considered likely that the 

 ancestral form of these cultivated grasses was a large much- 

 branched grass "each branch being terminated by a tassel-like 

 structure bearing hermaphrodite flowers." As evolution pro- 

 gressed, the lateral branches of maize came to bear only pistillate 

 flowers and the central branch staminate flowers. This theory 

 is strengthened by the types of inflorescence which frequently 

 appear in maize varieties. Often the central spike of the tassel of 

 lateral branches bears seeds, while the side branches of the same 

 tassel bear only staminate organs. All gradations appear 

 between the normal ear of maize and the staminate tassel. It is 

 not uncommon in self-fertilized maize races to obtain plants in 

 which the tassel of the main branch bears both male and female 



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