Hayes and Garber - Cucurbit Breeding

124 BREEDING CROP PLANTS
correlation coefficient. The coefficients for the years 1914,
1915, 1916, and 1917 were 0.143 O.C38, 0.088 0.028, 0.445
0.020, and 0.478 0.024, respectively. In this investigation
each plant was given the same space for individual development.
The results show that under these conditions relatively large
amounts of stored plant food in the germinating seed may or
may not give the resultant plants an advantage, depending on
environmental influences other than the amount of endosperm.
Several investigators have attacked this problem from a practical
viewpoint. Seeds were separated into light, medium, and
heavy by means of a fanning-mill. The productivity of the
plants coming from the various classes of seed was compared
under field conditions. Some investigators procured a slightly
greater yield from plants produced by heavy seed than from those
coming from light seed. Others obtained no such difference.
Plants from medium or ungraded seed in almost all cases proved
as productive as those from heavy seed. The work carried on
at the Ohio Station may be taken as a typical example of these
investigations.
Table XXIV presents the average results (Williams and Welton,
1911) of an experiment with weight of seed wheat over a period of
seven years. The grades are first, second, and third, representing
heavy, medium, and light seed, respectively. Two methods
of seeding were practiced, namely, a uniform rate by weight and
a varied seeding to obtain approximately an equal number of
plants on equal areas.
TABLE XXIV.
THE RELATION OF WEIGHT OF GRAIN TO YIELD IN WHEAT
Seven-year Average Results
Grade