20 BULLETIN 1489, IT. S. DEPARTMENT OF AGRICULTURE 
When anther-ear plants (an an, D D) are crossed with dwarf 
plants (An An, d d) , the F x plants are normal, being heterozygous 
for both factor pairs (An an, D d). In the F 2 generation, normal, 
dwarf, anther-ear, and dwarf anther-ear plants appear in approxi- 
mately a 9:3:3:1 ratio. This is the dihybrid Mendelian ratio that 
would be expected, as shown below. 
1 AnAn,DD 
2 AnAn T D d 
2 An an, D D 
4 An an,D d\ 
9 normal. 
1 An An, d d 
2 An an-, d d 
1 an an, D D 
2 an aih D d 
3 dwarf. 
3 anther ear. 
1 an an, d d=l dwarf anther ear. 
The point of special interest is that the dwarf anther-ear form 
(an an, d d) is notably shorter than the dwarf form (An An, d d), 
showing conclusively that the recessive factors are cumulative in 
their shortening effect and that size is affected by complementary 
factors just as are such characters as endosperm color {23). 
PODDEDNESS 
The podded condition in corn is due to the fact that the glumes, 
which ordinarily are rudimentary in the female inflorescence, develop 
and inclose each kernel in a husklike structure, giving the character- 
istic appearance shown in Plate 6, A. This character is of especial 
interest for several reasons. In the earlier classifications of corn it 
was made the basis for a botanical species called Zea timicata. This 
type also has been widely advertised as " primitive corn," and it has 
been considered as an approach, at least, to the wild type. 
The podded condition is controlled by the factor pair Tu tu. Nor- 
mal corn is homozygous recessive, tu tu, whereas podded ears are 
heterozygous, Tu tu. The homozygous dominant form (Tu Tu) 
does not bear seed in the lateral inflorescence (ear), but may be 
propagated from seeds produced in the tassel (11). This statement, 
of course, applies to the factor pair Tu tu, the effect of which has 
been determined experimentally. It is entirely possible that a simi- 
lar podded condition may be caused by some other factor pair which 
at the same time will permit the development of seeds on the ear. 
Plate 6, B shows an ear of corn in which the podded condition 
decreases progressively from butt to apex. This ear is from the 
same parent as the one shown in Plate 6, A. Its behavior in in- 
heritance has not been determined, and it is shown only as an example 
of the complexities that may occur in the inheritance of some com- 
paratively simple characters. Characters are spoken of as controlled 
or determined by certain factors that segregate and recombine in this 
or that proportion. Such statements are entirely true in their 
broader sense, and it is necessary thus to reduce the problems to their 
simplest terms if progress is to be made. One instance of inheritance 
after another that seemingly was at variance with Mendelian princi- 
ples has been demonstrated to come within them when carefully 
analyzed. It therefore seems justifiable to omit the minor complexi- 
ties from consideration in general, in order to grasp more readily 
the broader underlying principles. It is equally advisable to stop 
now and then for a glimpse of the details. In few cases is inheritance 
