﻿PLANT 
  BREEDING 
  

  

  181 
  

  

  3. 
  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 
  preeminently 
  an 
  

   American 
  plant. 
  At 
  the 
  time 
  of 
  the 
  discovery 
  of 
  America, 
  

  

  FIG. 
  156. 
  A 
  prize 
  ear 
  of 
  Johnson 
  County 
  White 
  corn 
  1 
  

   An 
  admirable 
  type 
  of 
  dent 
  corn. 
  Photograph 
  by 
  L. 
  B. 
  Clore 
  

  

  and 
  probably 
  for 
  a 
  long 
  period 
  before 
  that 
  tune, 
  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 
  11- 
  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. 
  2 
  

  

  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, 
  1007. 
  The 
  

   price 
  paid 
  was 
  $250. 
  

  

  2 
  See 
  Bulletin 
  57, 
  Office 
  of 
  Experiment 
  Stations, 
  U.S. 
  Dept. 
  Agr., 
  1899. 
  

  

  