﻿PLANT 
  INDUSTRIES 
  315 
  

  

  animal 
  enemies 
  that 
  the 
  plant 
  may 
  encounter 
  in 
  its 
  new 
  grow- 
  

   ing 
  place. 
  Thus 
  when 
  corn, 
  which 
  naturally 
  thrives 
  best 
  as 
  

   a 
  tropical 
  or 
  sub-tropical 
  plant, 
  is 
  grown 
  in 
  the 
  north 
  central 
  

   states, 
  the 
  shortness 
  of 
  the 
  season 
  may 
  not 
  allow 
  time 
  for 
  

   ripening 
  the 
  ear 
  ; 
  but 
  by 
  experimentation 
  certain 
  varieties 
  of 
  

   corn 
  have 
  been 
  discovered 
  or 
  developed 
  (see 
  chapter 
  on 
  Plant 
  

   Breeding) 
  in 
  which 
  the 
  plant 
  is 
  not 
  so 
  large 
  as 
  the 
  average, 
  

   and 
  the 
  ear, 
  though 
  somewhat 
  smaller, 
  matures 
  in 
  less 
  time. 
  

   Some 
  kinds 
  of 
  seed 
  corn 
  are 
  advertised 
  by 
  the 
  salesmen 
  as 
  

   " 
  ninety-day 
  corn," 
  which 
  means 
  that 
  the 
  plant 
  will 
  grow 
  and 
  

   ripen 
  a 
  new 
  ear 
  within 
  ninety 
  days, 
  while 
  in 
  case 
  of 
  some 
  

   other 
  varieties 
  of 
  corn 
  more 
  than 
  double 
  that 
  time 
  is 
  required 
  

   for 
  it 
  to 
  mature. 
  Furthermore, 
  in 
  the 
  case 
  of 
  wheat 
  some 
  

   varieties 
  are 
  much 
  less 
  readily 
  affected 
  by 
  the 
  rust 
  diseases 
  

   than 
  are 
  other 
  varieties 
  ; 
  some 
  thrive 
  best 
  in 
  certain 
  regions 
  

   when 
  planted 
  in 
  the 
  late 
  autumn 
  (winter 
  wheat) 
  ; 
  and 
  others 
  

   in 
  other 
  regions 
  thrive 
  best 
  when 
  planted 
  in 
  early 
  spring 
  

   (spring 
  wheat). 
  Every 
  civilized 
  or 
  even 
  partially 
  civilized 
  

   nation 
  depends 
  largely 
  upon 
  one 
  or 
  more 
  of 
  the 
  cereals, 
  and 
  

   in 
  spite 
  of 
  the 
  fact 
  that 
  the 
  nations 
  have 
  been 
  dependent 
  upon 
  

   them 
  for 
  so 
  long, 
  the 
  practices 
  relative 
  to 
  selection 
  of 
  seed, 
  

   cultivation, 
  prevention 
  of 
  diseases, 
  and 
  utilization 
  of 
  the 
  prod- 
  

   ucts 
  have 
  changed 
  very 
  little 
  from 
  decade 
  to 
  decade. 
  The 
  

   application 
  of 
  scientific 
  principles 
  to 
  the 
  production 
  of 
  cereals 
  

   has 
  already 
  shown 
  great 
  possibilities 
  of 
  improvement 
  in 
  plant 
  

   production, 
  but 
  only 
  the 
  most 
  intelligent 
  agriculturists 
  utilize 
  

   these 
  investigations, 
  the 
  traditional 
  " 
  practices 
  of 
  the 
  fathers 
  " 
  

   often 
  dominating 
  the 
  majority 
  of 
  those 
  who 
  till 
  the 
  soil. 
  No 
  

   doubt 
  the 
  decades 
  immediately 
  to 
  follow 
  will 
  bring 
  much 
  new 
  

   scientific 
  knowledge 
  about 
  the 
  growth 
  of 
  cereal 
  crops, 
  and 
  

   nothing 
  seems 
  more 
  fundamental 
  than 
  the 
  application 
  of 
  those 
  

   sciences 
  which 
  may 
  lead 
  to 
  a 
  more 
  effective 
  production 
  of 
  the 
  

   world's 
  food 
  supply. 
  

  

  298. 
  Horticulture. 
  Fruits 
  and 
  berries 
  have 
  constituted 
  a 
  

   considerable 
  part 
  of 
  the 
  food 
  of 
  men 
  throughout 
  the 
  period 
  

   covered 
  by 
  history. 
  Wild 
  apples, 
  grapes, 
  and 
  berries, 
  in 
  nearly 
  

  

  