STERILITIES OF WILD AXD CULTIVATED POTATOES. 
15 
Table 1. — Potato crosses grouped according to pollen parent recorded by the United 
States Department of Agriculture during the 9-year period from 1914 to 1922, inclv- 
sive — Continued . 
Date of 
crossing. 
Parents. 
Aug. 5,1917 t Franceses Colorada (S. A. No. S6)XSwitez. 
Aug. 8,1914 j Radium xSwitez 
Do Rust ProofxSwitez 
Aug. 5, 1917 | Solanum sp. ( S. A. No. 37) x Switez 
Do j Solanum sp. (S. A. No. 48)xSwitez 
Do I Solanum sp. (S. A. No. 69)xSwitez 
Aug. 7,1914 
Do 
Aug. 7,1914 
Do 
Total and average. 
Earlv Eurekax Triumph 
Early Standard (Dreer's)xTriumph. 
Total and average . 
Early Michiganx Venezuela. 
Garnet Chili x Venezuela 
Total and average. 
Classes 
involved 
t in cross. 
July 27,1916 j Up-to-Datex White Albino (Ace. No. 19393). .. 
Aug. 10,1914 British QueenX Zbyszek 
Do , Late Vicktor X Zbyszek 
Do McCormickX Zbvszek 
Do Non Blight X Zbyszek 
Do ; Prosperity X Zbyszek 
Do ' Rural New Yorker x Zbyszek 
Tot-al and average . 
AX1 
-XI 
— X'. 
—XI 
-XI 
-XI 
Number of— 
Flowers' ged 
cro * sed - produced 
-X3 
— X3 
AX- 
AX- 
-X3 
BXl 
AXl 
AX1 
AXl 
AXl 
AXl 
11 I 
5 
10 
4 
3 
37 
12 
51 
2o 
Percent- 
age of 
success. 



25.00 


2.70 

80.00 
12.50 
80.00 
60.00 
28.57 
43.86 
The results for 10 varieties whose records show good seed production 
(class A) are brought together in Table 2, the data being arranged 
according to the class in which the male parent belongs with respect 
to the quality of its pollen. 
These 10 varieties produced seed balls in 40 per cent of the flowers 
crossed with pollen of class 1, in 13 per cent of the flowers crossed 
with pollen of class 2, and no fruit for 155 flowers crossed with pollen 
of class 3. 
It appears that some varieties have produced seed balls rather 
feebly even when the best pollen has been used. The data for four 
such varieties which have been placed in class B are also assembled 
in Table 2. Of the total of 305 flowers crossed with pollen of class 1, 
only 8 per cent produced seed balls. 
Several of the varieties listed in class B are known to be poor 
flower producers, even at Presque Isle. Few flowers open and 
the early abscission of these is marked. This suggests that the 
feeble production of fruits by such varieties is directly limited by 
this condition and possibly can be changed by growing these varieties 
under conditions which decrease abscission and favor abundant 
blooming. Varieties in class A blooming at the New York Botanical 
Garden are lower in fruit production than at Presque Isle, giving 
more failures to self and cross pollinations with pollen of class 1. 
Comparative tests of pollen of the Clio, McCormick, Mclntvre, and 
Seedling 24642 varieties growing in both localities were made in 1922. 
There appeared to be no appreciable difference in quantities of pollen 
or in its viability, but the same combinations which were most 
