CORN BREEDING 
49 
i 
Table 7. — Comparative yields of the Century and Learning varieties of com and 
of Fi crosses and a double cross oetiveen selfed lines of these varieties in 
Connecticut 
[Data from Jones and Mangelsdorf (43, V- 182)] 
Designation 
Acre* 
yields 
(bushels) 
Century variety (110) . . .. 
47.5 
Learning variety (112) ... .... ... .. . .. 
44.4 
Single cross (110-2X110-4). . 
51.2 
Single cross (112-1X112-4) 
45.6 
Double cross (110-2 X 110-4) X (112-1X112-4)) 
69.8 
The results of extensive comparisons of crosses between selfed 
lines and the parent variety made at the Nebraska station have been 
reported by Kiesselbach (48). A summary of the data on crosses 
between selfed lines from the high-yielding stock of the Hogue 
variety is given in Table 8. 
Table 8. — Comparative yields of Hogue corn and of crosses oetiveen selfed 
lines of this variety at Lincoln, Neor., in years stated 
[Data from Kiesselbach Q8, p. 53)] 
Designation 
Acre yields of shelled 
corn (bushels) 
1913 
1915 
1916 
1917 
Average 
Crosses between selfed lines: 
4X12_ 
22.0 
26.8 
22.8 
20.1 
21.9 
22.7 
24.2 
25.6 
61.9 
64.8 
7L3 
73.6 
57.9 
61.0 
75.4 
38.8 
53.2 
44.6 
66.2 
58.0 
51.5 
43.3 
58.2 
60.6 
41.6 
48.5 
51.9 
59.4 
53.6 
51.0 
45.2 
45.8 
4X1 . 
46 6 
12X5_ 
46.4 
8X2 
52 4 
12X2 
53 2 
10X12 
46 4 
10X5 -.. 
44 9 
2X10 
51 1 
Average .. . 
23.3 
66.9 
51.7 
51.5 
48.3 
Original Hogue . ... .. .. 
11.4 
73.1 
34.5 
46.0 
41.2 
The average yield of the crosses exceeded the yield of Hogue in three 
of the four years for which data are reported. Whether the failure 
of many of the crosses to yield more in 1915 was due to the fact 
that the crosses were adapted better to a lower level of productivity 
than obtained in that year is not known, though the data suggest 
such a possibility. Two of the crosses, however (12X2 and 2X10), 
yielded more than Hogue in each year, their average increase for the 
four years being 29.1 and 24 per cent, respectively. It is characteris- 
tic of experiments of this kind that the three leading crosses had a 
single line (No. 2) as one parent. 
Kiesselbach (4<§, p. 63) also reports the yields of crosses between 
selfed lines selected from stocks of the Hogue variety having high 
leaf area and low leaf area. Of the 29 crosses for which data are 
reported, 20 yielded more and 9 yielded less than the parent variety, 
as an average for the years 1915 and 1916. The average acre yield 
of the 29 crosses was 60.2 bushels in comparison with 55.1 bushels 
for Hogue. It should be emphasized again that, although it is inter- 
