1044 
Journal of Agricultural Research 
Vol. XXXI, No. 11 
REVIEW OF LITERATURE 
Investigators working with a great many varieties have found that 
for the most part large, heavy seeds produce plants of greater size 
and higher yield than small ones, and the crop is more uniform. 
Other investigators, however, have found the results of their work 
conflicting or inconclusive. A brief resume of published data is 
given here in order that the scope of the investigations may be under¬ 
stood, but it is not intended to include all that have been reported. 
Deherain and Dupont (3 ) 3 claim that a definite advantage in favor 
of heavier seed shows only when the difference in weight is great. 
Myers (10), working with wheat, found his results inconclusive. 
Leighty (8) criticizes the method of selecting large seed without 
knowing something of the characteristics of the mother plant. 
Love (9), in his work with wheat and oats, finds that the heaviest 
grains come from the tallest and heaviest yielding plants. Johann- 
sen ( 5 ), from his studies of the inheritance of weight of bean seeds, 
concludes that the heaviest daughter beans are the progeny of the 
heaviest mother beans, but that this does not necessarily hold in 
a pure line. DeVries (15), on the other hand, thinks that size and 
weight of seeds are the result of nutrition in the broad sense rather 
than of inheritance. 
Studies have also been made of seeds in relation to their specific 
gravity. Haberlandt’s (4) work with wheat and oats shows that 
the denser kernels yield heavier returns in grain and the lighter 
kernels yield greater quantities of straw. Wollny (16) maintains 
that its absolute weight and not its specific gravity is the true index 
to the value of grain. Clark ( 1) finds that size of seed is the most 
important factor for selecting within a variety, that is, the heaviest 
seed in a given size (volume) gives the best results. 
In studying the combined effects of size and specific gravity, 
Sanborn (14) found that the yield from the lighter grains of wheat 
is greater than from the heavier ones. Degrully (2), working with 
corn, discarded all of the very small and poorly formed kernels and 
separated out the lightest one-fourth of the remainder by means of 
sodium nitrate solution. The difference in results in favor of the 
heavy kernels was very striking. He also found that wheat seedlings 
from heavy grains are greener, more vigorous, and greatly superior 
to those from lighter grains. These differences, he believes, are the 
result of some factor inherent within the seed. Kiesselbach and 
Helm (6) found that the total “sprout values” of unselected grains 
and large and small grains of wheat were, respectively, 100, 123, 
and 100.88. These figures indicate a rather close relationship 
between the size of seed and its sprout value. Kisselbach ana 
Cook (7) working with corn find that increases in kernel weight may 
be due to two causes: (1) heterosis (11.8 per cent) as in crosses in 
selfed strains, and (2) a change in type of endosperm (19.9 per cent), 
as sweet corn crossed with dent or flint varieties. Commercial dent 
varieties, being already heterozygous, respond relatively little (0.2 
per cent increase) to the immediate effect of foreign pollen as a result 
of heterosis. Pearl and Surface (11), Working with corn, found that 
there is a marked tendency for the plants which were relatively small 
3 Reference is made by number (italic) to “Literature cited,” page 1052. 
