Wheat  and  Barley  Experiments. 
341 
six  and  two  row,  bearded  and  beardless,  bearded  and  hooded, 
lax  and  dense,  black  and  white  races,  &c.  Both  cereals  are 
self-fertilised  and  the  cross-breds  are  fertile. 
Taking,  first  of  all,  some  exaraj^les  from  wheat,  the  results 
of  crossing  races  showing  certain  characters  are  shown  in  the 
The  characters  appearing  in  the  ci'oss-bred  are  the  dominant 
ones,  the  corresponding  recessives  being  dense,  bearded,  smooth 
chaff,  white  grain  or  chaff,  and  round  glumes.*  With  one 
exception  the  dominant  characters  mentioned  above  appeared 
in  full  intensity  in  the  cross-breds.  The  length  of  the  beard, 
the  bright  red  of  the  chaff,  &c.,  underwent  no  diminution.  The 
exception  is  the  case  where  Rivet  wheat  was  used  as  a rough- 
chaffed  parent.  Then  the  cross-breds  were  not  as  velvety  as  the 
Rivet  wheat.  If  Rough  Chaff  or  Old  Hoary  was  ufjed  then  this 
character  appeared  in  full  intensity.  The  cross-breds  differed 
in  one  respect  though  from  the  doniinant-character-bearing 
parental  form.  They  were  peculiarly  vigorous ; first  crosses 
with  Rivet  wheat  being  often  fully  seven  feet  high,  whilst 
their  tillering  power  was  enormous.  After  self-fertilisation 
the  progeny  of  the  cross-breds  consisted  approximately  of 
three  dominant  to  one  recessive  form,  e.g.,  bearded  : beard- 
less : : 118  : 43,  in  another  cross  as  273  : 91 ; rough  chaff  : 
smooth  : : 104  : 35,  in  another  experiment  as  373  : 140  ; red 
chaff  : white  : : 329  : 115,  &c.  The  following  generation 
showed  that  the  recessive  forms  bred  true  to  type  in  all  cases, 
but  that  the  dominant  type  was  composed  of  individuals 
which  either  bred  true  to  type  or  again  “broke”  into  dominant 
and  recessive  types  in  the  ratio  of  3 : 1,  and  this  in  spite  of 
the  fact  that  one  could  distinguish  no  difference  between 
them.  This  generation  then  consisted  of  pure  recessive,  pure 
dominant,  and  cross-bred  forms  ; and  a statistical  examination 
of  many  cases  showed  these  to  be  present  in  the  average 
proportion  of  1 : 1 : 2. 
The  breeder  must  note,  then,  that  external  appearances  are 
no  guide  to  the  purity  of  any  individual  that  depends  solely  on 
its  gametic  condition  ; the  one  test  is  to  breed  from  it.  For 
instance,  an  animal  may  appear  to  be  a pure  Aberdeen  Angus, 
in  reality  it  may  be  a cross-bred  Shorthorn  Angus,  and  crossing 
with  the  recessive  type  (the  Shorthorn)  alone  will  settle  the  point. 
* Many  other  pairs  of  characters  have  been  investigated,  but  a consideration 
of  these  must  suffice  for  the  present. 
Table 
Red  X white  grain  or  chaff 
Keeled  x rounded  glumes  . 
Beardless  X bearded  . 
Rough  X smooth  chaff 
Parental  Characterx. 
I^ax  X dense 
Character  of  Croxx-hredx. 
Lax. 
Beardless. 
Rough  chaff. 
Retl  grain  or  chaff. 
Keeled  glumes. 
