﻿PLANT 
  BREEDING 
  191 
  

  

  books. 
  Careful 
  study 
  of 
  the 
  gardens 
  or 
  fields 
  of 
  some 
  suc- 
  

   cessful 
  breeder 
  is 
  also 
  necessary. 
  The 
  five 
  rules 
  which 
  follow 
  

   are 
  here 
  given 
  only 
  to 
  illustrate 
  some 
  of 
  the 
  precautions 
  

   necessary 
  to 
  insure 
  success. 
  

  

  1. 
  For 
  breeding 
  experiments 
  choose 
  plants 
  like 
  wheat, 
  corn, 
  

   and 
  apples, 
  which 
  naturally 
  show 
  many 
  varieties 
  or 
  elementary 
  

   species 
  (fig. 
  163). 
  

  

  2. 
  Breed 
  for 
  one 
  

   character 
  at 
  a 
  time 
  ; 
  

   that 
  is, 
  do 
  not 
  try 
  

   to 
  get 
  such 
  a 
  prod- 
  

  

  uct 
  as 
  a 
  strawberry 
  

   i 
  i 
  I 
  ii 
  FIG. 
  163. 
  Four 
  extremely 
  unlike 
  varieties 
  of 
  apple 
  

  

  selected 
  from 
  thirty- 
  six 
  varieties, 
  all 
  seedlings 
  of 
  

   most 
  Others 
  in 
  size, 
  the 
  Early 
  Williams 
  apple 
  

  

  Sweetness, 
  bearing 
  Modified 
  from 
  photograph 
  by 
  Burbank 
  

  

  qualities, 
  and 
  abil- 
  

   ity 
  to 
  stand 
  shipping 
  long 
  distances 
  - 
  - 
  all 
  the 
  desirable 
  quali- 
  

   ties 
  in 
  one 
  berry. 
  

  

  3. 
  Do 
  not 
  try 
  to 
  get 
  opposite 
  qualities 
  in 
  the 
  same 
  breed. 
  

   For 
  instance, 
  corn 
  cannot 
  be 
  bred 
  for 
  high 
  percentage 
  of 
  

   starch 
  and 
  of 
  protein 
  at 
  the 
  same 
  time. 
  

  

  4. 
  Choose 
  plants 
  for 
  seed 
  by 
  inspection 
  as 
  they 
  grow 
  in 
  

   the 
  field. 
  A 
  melon 
  or 
  a 
  cucumber 
  plant 
  which 
  bears 
  many 
  

   rather 
  large 
  fruits 
  is 
  likely 
  to 
  be 
  a 
  better 
  parent 
  than 
  a 
  plant 
  

   which 
  bore 
  only 
  one 
  very 
  large 
  fruit. 
  The 
  total 
  product 
  of 
  the 
  

   individual 
  should 
  be 
  ascertained 
  by 
  field 
  study, 
  and 
  the 
  vigor 
  

   and 
  general 
  condition 
  of 
  the 
  plant 
  should 
  be 
  carefully 
  noted. 
  

  

  5. 
  Keep 
  up 
  the 
  type 
  by 
  constant 
  selection 
  of 
  the 
  best 
  indi- 
  

   viduals 
  for 
  seed, 
  even 
  after 
  breeding 
  has 
  resulted 
  in 
  securing 
  

   plants 
  that 
  come 
  up 
  to 
  the 
  desired 
  standard. 
  This 
  is 
  abso- 
  

   lutely 
  necessary 
  in 
  perpetuating, 
  for 
  instance, 
  the 
  variations 
  

   which 
  make 
  the 
  difference 
  between 
  the 
  sweetest 
  and 
  the 
  

   poorest 
  sugar 
  beets 
  ; 
  but 
  it 
  is 
  also 
  useful 
  in 
  keeping 
  such 
  

   elementary 
  species 
  as 
  wheat 
  varieties 
  up 
  to 
  the 
  highest 
  stand- 
  

   ard, 
  because 
  the 
  seed 
  of 
  a 
  desirable 
  variety 
  might 
  be 
  taken 
  

   from 
  imperfect 
  or 
  diseased 
  ears 
  and 
  yield 
  a 
  poor 
  crop. 
  

  

  