INHERITANCE OF WAXY ENDOSPERM IN MAIZE. 97 
than the pollen tubes from the grains bearing the odd combinations. 
Such a difference in the rate of growth would not occur in the female 
gametes, and they would be present in the theoretical proportions 
unless a differential death rate supervened. 
Tt does not seem unreasonable to believe that any reaction, which 
causes the more rapid division of the cells bearing the correlated 
characters, may also cause the gametes with these same combinations 
to be more vigorous. In most cases when an ear is pollinated there 
are enough pollen grains on each stigma to insure the presence of all 
gametic combinations, and if any difference in the rate of growth 
prevailed for a certain gametic combination most of the seeds would 
be fertilized by that combination. 
CONCLUSION. 
A thorough understanding of the laws of heredity is essential in 
determining the most effective methods of breeding plants and ani- 
mals with the special characters that are needed for purposes of com- 
mercial production under different environmental conditions. It is 
of general interest to practical breeders at the present time to know 
the extent to which it is possible to rely upon the application of the 
Mendelian principles of heredity. Assurance has been given by cer- 
tain writers that analysis and recombination of characters of varie- 
ties by the Mendelian methods could be substituted to advantage for 
the methods of selection that have been considered as the most 
effective means of obtaining improved strains. ~ 
An adequate investigation of the current theories in regard to the 
laws of heredity requires the detailed analysis of results derived from 
the study of large numbers of individuals. In this respect the seeds 
of maize offer unusual opportunities. Instead of a single offspring, 
or a few, from 400 to 800 seeds result from a single application of 
pollen, and the technique of hybridization is extremely simple. In 
addition to the ease of manipulation and the relatively. large num- 
bers obtained, maize seeds offer the further advantage of several 
alternative characters which permit rapid and accurate classification. 
This makes possible the definite determination of questions which 
depend upon the regularity of the proportions in which the charac- 
ters are represented in the various hybrid stocks. 
With these possibilities in view, the experiments reported in this 
bulletin were undertaken in 1910, to analyze further the inheritance 
of contrasted characters and to obtain a clearer understanding of 
the nature of the interrelations or correlations between such charac- 
ters. The characters chosen were the waxy endosperm texture found 
in a variety of maize from China and the colors of the aleurone cells 
with which this endosperm texture was known to be associated. 
89356°—19——7 
