Plant-Breeding for Farmers. 165 



narily does not require an extensive test as the experience of growers in a 

 region has usually shown the general superiority of a comparatively few 

 varieties and the test can thus be limited to these varieties which in 

 general are known to be the best. The writer would not urge this test 

 of varieties, if it were not very important to begin any breeding-work 

 with the best variety available. Breeding-work requires so much at- 

 tention, that it does not pay to start work with an inferior variety. The 

 first work of anyone contemplating breeding with potatoes is thus, 

 determining the best foundation stock to use for the selection work. 

 If the grower has had extensive experience in growing potatoes and has 

 determined that a certain variety gives the best results under his condi- 

 tions, he is in position to start the selection work without a further test of 

 varieties. 



Grozving potatoes for selection. 



The influence of the number of eyes and size of piece planted as seed 

 has so much to do with the yield of the hill that fields planted in the 

 ordinary way are very poorly adapted to begin the work of selection. 

 It is of primary importance that the first selections made be of the very 

 highest type obtainable, as it is a common experience that the first selec- 

 tion is the most important. Too much attention cannot be given 

 therefore, to the first selection. The writer would thus urge the following 

 method as one of the most satisfactory to be pursued: 



( 1 ) Examine a large number of tubers of the variety selected as the 

 foundation stock and decide on the most desirable shape and type of 

 tuber. In general a moderately large tuber, which is oblong or some- 

 what cylindrical in shape and oblong in cross section is considered most 

 desirable (Fig. 10). A spherical tuber if sufficiently large to be desirable 

 is so thick that in cooking, the outside is liable to become over done before 

 the interior is properly cooked. A tuber with shallow eyes, netted surface 

 and white color, is also usually preferred. 



(2) When the ideal character and size have been determined, 

 examine a large number of tubers and pick out a thousand or more 

 having this size, shape and general character. This is work that can be 

 done in the late fall and winter when there is no rush of other farm work, 

 and time should be taken to obtain a considerable number of these tubers 

 of the same character. These are to be used as the seed for planting the 

 selection-plot and the number selected should correspond to the size of 

 the plot which it is desired to plant, four hills being planted with each 

 tuber. There should certainly not be less than 1000 and a much larger 

 number is very desirable. The prospective breeder should remember 

 that success in- breeding-work depends upon selecting the one individual 

 that gives the very highest yield possible under the conditions, and the 



