Hayes and Garber - Cucurbit Breeding

CHAPTER XIV
MAIZE BREEDING
Maize was the most important bread crop of the American Indians
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 Maydese of the order Graminese. All varieties of Indian
corn are placed in the species mays. The nearest relative of
maize is teosinte, Euchlcena 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 Euchlaena and normal teosinte. Montgomery
(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 muchbranched
grass "each branch being terminated by a tassel-like
structure bearing hermaphrodite flowers." As evolution progressed,
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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