﻿182 
  Harper: 
  Inheritance 
  of 
  sugar 
  

  

  ^ 
  

  

  sperm 
  shows 
  a 
  tendency 
  to 
  produce 
  starch 
  in 
  greater 
  proportions 
  

   as 
  a 
  reserve 
  carbohydrate 
  throughout 
  the 
  Hfe 
  of 
  the 
  endosperm 
  

   cells. 
  Such 
  tendencies 
  or 
  qualities 
  need 
  not 
  be 
  conceived 
  as 
  

   represented 
  but 
  as 
  actually 
  present 
  as 
  such 
  in 
  the 
  germ 
  cells, 
  and 
  

   as 
  coming 
  to 
  expression 
  in 
  varying 
  degrees 
  according 
  to 
  the 
  

   position 
  of 
  the 
  cell 
  in 
  the 
  multicellular 
  plant 
  body 
  and 
  its 
  corres- 
  

   ponding 
  opportunity 
  for 
  the 
  formation 
  of 
  storage 
  products. 
  

   We 
  of 
  course 
  need 
  much 
  further 
  data, 
  both 
  histological 
  and 
  cyto- 
  

   logical 
  as 
  to 
  the 
  sweet 
  and 
  starchy 
  kernels 
  but 
  no 
  facts 
  so 
  far 
  

   known 
  are, 
  as 
  it 
  seems 
  to 
  me, 
  inconsistent 
  with 
  the 
  conception 
  

   of 
  these 
  characters 
  as 
  metidentlcal 
  form 
  qualities 
  which 
  can 
  be 
  

   classed 
  with 
  the 
  metidentlcal 
  color 
  characters 
  which 
  are 
  so 
  com- 
  

   mon. 
  That 
  such 
  form 
  characters 
  must 
  be 
  conceived 
  as 
  the 
  

   expression 
  of 
  a 
  definite 
  number 
  of 
  unit 
  factors 
  invariable 
  except 
  

   for 
  relatively 
  rare 
  and 
  strongly 
  marked 
  mutations, 
  seems 
  to 
  me 
  

   quite 
  contrary 
  to 
  the 
  evidence 
  as 
  it 
  exists. 
  The 
  fluctuating 
  

   behavior 
  of 
  these 
  characters 
  with 
  the 
  presence 
  of 
  all 
  possible 
  

   intergradation 
  from 
  the 
  extreme 
  of 
  starchy 
  to 
  the 
  extreme 
  of 
  

   sweet, 
  as 
  shown 
  in 
  Figs. 
  167 
  &-167 
  /, 
  suggests 
  modification 
  and 
  

   fluctuating 
  variability 
  rather 
  than 
  mathematical 
  fixity 
  in 
  the 
  

   cellular 
  basis 
  of 
  these 
  characters. 
  The 
  fact 
  that 
  selection 
  does 
  

   not, 
  at 
  least 
  at 
  once, 
  eliminate 
  the 
  extremes 
  of 
  the 
  series 
  of 
  variants 
  

   is 
  opposed 
  to 
  the 
  conception 
  of 
  such 
  variability 
  being 
  due 
  to 
  recom- 
  

   bination 
  of 
  multiple 
  fixed 
  factors. 
  Typically 
  starchy 
  kernels 
  

   and 
  typically 
  sweet 
  kernels 
  recur 
  in 
  the 
  F3 
  and 
  F4 
  generations, 
  as 
  

   is 
  shown 
  in 
  the 
  tables. 
  The 
  number 
  of 
  generations 
  is 
  small, 
  but 
  

   the 
  case 
  is 
  one 
  again 
  in 
  which 
  the 
  relative 
  proportion 
  of 
  the 
  varying 
  

   types 
  is 
  changed 
  by 
  selection 
  without 
  the 
  immediate 
  elimination 
  

   or 
  the 
  obviously 
  proportionate 
  elimination 
  of 
  variability. 
  This 
  

   series 
  was 
  not 
  continued 
  further, 
  as 
  other 
  intermediate 
  types 
  

   seemed 
  more 
  promising 
  for 
  productiveness 
  and 
  other 
  matters 
  of 
  

   interest. 
  As 
  noted 
  above, 
  further 
  data 
  will 
  be 
  given 
  in 
  connection 
  

   with 
  the 
  description 
  of 
  such 
  intermediates 
  as 
  a 
  possible 
  race 
  of 
  

   meal 
  corns. 
  All 
  of 
  the 
  starch 
  X 
  sugar 
  crosses 
  which 
  I 
  have 
  studied 
  

   show 
  in 
  general 
  a 
  similar 
  fluctuating 
  variability, 
  with 
  a 
  tendency 
  

   to 
  the 
  inheritance 
  of 
  the 
  Intermediate 
  condition 
  when 
  it 
  appears. 
  

   The 
  intermediates 
  obtained 
  in 
  the 
  Wisconsin 
  White 
  Dent 
  X 
  Black 
  

   Mexican 
  Sweet 
  cross 
  may 
  be 
  taken 
  as 
  illustrative, 
  so 
  far 
  as 
  my 
  

  

  