18 BULLETIN 195, U. S. DEPARTMENT OF AGRICULTURE. 
The 6 seed balls from cross 8708, Irish Cobbler X Irish Seedling, in 
which but 6 flowers were pollinated, produced a total of 964 seeds, or 
an average of 160.7 seeds per berry. The number of seeds in each 
berry varied from 57 in seed ball d to 256 in seed ball e. A fair degree 
of uniformity in the percentage of germination is to be noted. 
The cross 8709, Irish Cobbler X Irish Seedling, resulted in 5 seed 
balls from 7 flowers pollinated, and these developed 984 seeds, or an 
average of 196.8 seeds per berry. The number of seeds from the 
individual seed balls ranged from 134 to 289 and the percentage of 
germination from 71.6 to 91.3. 
In the thud cross, 8718, Eureka X Keeper, 5 seed balls resulted 
from 7 flowers pollinated, and these produced 1,154 seeds, or an aver- 
age of 230.8 seeds per berry, the percentage of germination varying 
from 73.1 to 84.1. 
The highest number of seeds from an individual seed ball was from 
8718-5, which produced 297 seeds. Another point of interest in 
these crosses which has not as yet been emphasized is that the seed 
balls were produced in each case on the same cyme or flower cluster. 
It is generally believed by potato breeders that the raising of more 
than one or two seed balls in a cluster is undesirable. On this point 
East * says: 
It is also desirable to stimulate the growth activity in the flower stalk by pollinating 
four or five flowers on one cyme; then after the berries are partially developed, pinch 
off the poorest and allow only two to develop to maturity. 
In a more recent publication 2 East states that the propriety of this 
procedure is doubtful. 
In view of the data which have just been presented it does not 
appear that the development of seed was curtailed in the slightest, 
with the possible exception of 8708-d, or that the germination was 
impaired, at least not so far as any data are available to refute it. It 
is true that the germination as a whole is not high for solanaceous 
seeds; yet if we take into consideration the fact that every seed 
removed from the seed ball was counted and that the number of 
seedlings given is the actual number that reached the potting stage, 
the showing made should be considered very satisfactory. 
METHOD OF GROWING AND TESTING SEEDLINGS. 
In order to insure a good development during the first season it is 
rather essential that the seedling should be allowed a long growing 
period. To do this it is necessary to start the seeds in a greenhouse 
or in a hotbed. In the latitude of Washington, in order to insure 
stocky plants in 3-inch pots, ready to be transferred to the field early 
i East, E. M. Technique of hybridizing the potato. In Proc. Soc. Hort. Sci., 1907, p. 35-40, 1908. 
(Seep. 39.) 
2 East, E. M. Some essential points in potato breeding. Conn. Agr. Exp. Sta., 31st and 32d Rpt. 
(1907-08), p. 429-447, pi. 41, 1908. (See p. 441.) 
