CORN BREEDING 
51 
other Southern States. Increased yields obtained from crosses be- 
tween selfed lines above the yield of this variety consequently rep- 
resent approximately the superiority of these crosses over the best 
commercial varieties available for this section. Data on the yields 
of crosses between selfed lines of Delta Prolific in Arkansas and 
Tennessee have been reported (63, 6J1). The superiority or inferior- 
ity of each of 74 crosses to Delta Prolific based on the yields at 
Knoxville, Tenn., in 1923 is shown in Table 10, the data being 
arranged to show strain tendencies. 
Of the 74 crosses for which data are shown, 29 yielded more and 
45 yielded less than the parent variety. The individuality of cer- 
tain lines in crosses is very evident. Thus, crosses of three lines of 
5-1- with 2-2-2-4-2-1 are slightly superior to the parent variety, 
whereas the same lines crossed with 2-2-2-4-4-1 produced decidedly 
inferior yields. The outstanding lines of the experiment are those 
of the 10-3-1 strain. Of the 74 crosses, 11 involved a line of 10-3-2- 
as one parent. Of the other 63, 26 yielded more and 37 yielded less 
than Delta Prolific. The value of 10-3-1- in hybrids is shown by 
the fact that it was one parent of 18 (69 per cent) of the superior 
crosses and of only 12 (32 per cent) of the inferior crosses. This 
is further evidence of the importance of selection on the basis of 
production in hybrid combinations, as the yields of the 10-3-1- selfed 
lines are not high. 
Some of the better yielding combinations included in the experi- 
ments in Tennessee were grown in comparison with the parent 
variety at Burdette, in 1925, from crossed seed produced at Knox- 
ville, Tenn., in 1924. The yields of these crosses as percentages of 
the yields of Delta Prolific grown in adjacent plats are given in 
Table 11. The yields of the same combinations as percentages of the 
yield of Delta Prolific grown in the same row at Knoxville, Tenn., 
are shown for comparison. 
Table 10. — Average yields of crosses bettceen selfed lines of Delta Prolific com 
above ( + ) or below (— ) the comparable yield of the parent variety at Knox- 
ville, Tenn., in 1923 
pat 
a from 
Richey and Mayer 
(64, V 
W] 
Increase above (+) or decrease below (— ) acre yields of shelled corn of parent 
variety (bushels) 
Pedigrees of parent lines 
CO 
IN 
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co 
N 
co 
4 1 
C<< 
IN 
IN 
<£> 
"* CO 
IN 
CO 
<N 
IN 
<N 
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IN 
CO 
2 
CO 
CO 
CO 
z 
cq 
i^ 
IN 
IN 
IN 
IN 
CO 
<N 
Tf 
5-1-2-2-1-3 
+1.3 
-20.5 
-18.6 
-36.9 
+2.1 
-6.9 
-4.4 
+9.0 
+3.4 
+.4 
-29.8 
-21.9 
-13.6 
5-1-2-3-2-2 
+ 4.0 
-20.9 
-20.4 
— 13.~1 
5-1-3-1-1-2 
5-1-3-3-1-2 
7-4-1-6-6-2 
+10.8 
+2.6 
-16.3 
-17.~6 
-1.0 
-15.1 
-11.3 
-14.8 
-6.1 
-6.6 
7-4-1-7-4-1 
7-4-2-1-1-2 
-20.~8 
+20." 6 
+6.4 
-5.6 
-8.3 
-1.5 
+30.0 
+16.1 
-2.1 
7-4-2-6-2-2. .. 
-20.4 
-1.5 
+2.1 
-8.6 
"+."i 
-18.8 
-1.8 
-4.0 
+15.8 
-12.8 
+6.9 
—8.3 
10-3-1-1-1-4 
-18.1 
-6.1 
+ii."6 
+6.4 
"+6."8 
+15.4 
4-15.0 
-10.4 
10-3-1-1-2-2 


—6.4 
10-3-1-2-1-4 or 5. 
4-3. 9 +22. ] 
+2.5 
10-3-1-2-2-3... 
+11.8 
+5.4 
-6.8-14.1 
-14.6 -8.0 
-7.9-17.3 
-6.8 
~+5.~5 
-29.~8 
+4.6 
+28.9 
10-3-2-1-2-1 
10-3-2-1-3-3 
-5.5 
