396 KARL B. KRISTOFFERSON 


In beans it is impossible to determine by mere inspection of the 
seed whether crossing has taken place or not; it is at once seen, 
however, when the F,-plant and its seeds are at hand. Thus it is 
necessary to grow another generation of the isolated plants. 
The experiments to be dealt with in this paper were begun in 
1918. Not less than 18 varieties in 162 isolations were tried that year. 
Unfortunately the labels of two-thirds of these isolations were destroyed 
during the cultivation of the field culture beans and could not be 
found again. The seeds of the remaining isolation were sown in the 
experimental field the following year, care being taken that the seeds 
from each plant were sown separately. Some of the lines did not 
germinate, and therefore only 44 remained to the definitive calculation. 
As experiments from only one year must be considered insuffi- 
cient I deemed it necessary to repeat the experiments in 1919. The 
number of varieties was reduced to 8, and these were sown in 123 
isolations in all. A great number of isolations were also destroyed 
this year, therefore only seeds from 86 plants could be sown the 
next year. 
The varieties used are classified as defined in the »Nordiska 
Jordbruksforskares Förening», viz. in shell-, sword-, break-, asparagus-, 
and wax-beans. The break- and asparagus-beans, however, have been 
brought together in one group: haricots vert. The varieties are put 
in the following main groups: 
Shell-beans Sword-beans Haricots vert Wax-beans 
Brown bean Broad sword Amerikansk repfri Wax flageolet 
Chocolate brown Dutch sword Chevrier 
Mottled brown Kaiser Wilhelm 100 to 1 
North star Saxonia 
Risbrinken Emperor of Russia 
Uppland 
Tables 1 and 2 give a comparison of the results obtained in the 
experiments. Col. 4 denotes the totals of the plants harvested from 
all the isolations of each variety, and col. 5 the number of plants 
received from the isolations when their seeds were sown in the ex- 
perimental field the following year. Table 3 shows the percentage 
of the crossings received from the main groups of beans. 
The percentage of hybrids was, as it appears from the tables, 
rather the same each year, and amounts to an average of 1,05 Yo. The 
