April, 1915.] The Inheritance of Size in Tomatoes. 
485 
The ideal plant fruit-size would have been obtained if it had 
been possible to harvest from each plant 1000 fruits or more and 
the modal average taken. As this could not be done, it was 
determined to select at least ten representative fruits from a plant, 
the arithmetical average of which would be considered the average 
fruit-size for that plant. In some cases, however, it was not 
possible to harvest at least ten fruits so that a few plants are 
represented by only four or five to nine recorded fruits. In the 
selection of the fruits to be gathered the greatest degree of care 
and accuracy was observed. One of the largest and one of the 
smallest fruits were first taken, after which the remaining fruits 
were selected as near to the mode of the fruit size as possible. It 
is believed that the deviation of the recorded fruit-weight of any 
plant, based on ten selected fruits, does not vary more than plus 
or minus .2 gram from the actual fruit-weight which would have 
been secured had all the normal fruits of that plant been harvested. 
But even if the error of plant fruit-size were twice that amount it 
would not materially affect the results of this work. 
RESULTS OBTAINED. 
The plants of the Yellow Pear tomato (carpellate parent) 
possessed the following average fruit-weights: 
2-11-16. Plant 2 = 19.26 grams. 
“ “ 3 = 17.84 
“ “ 4 = 12.71 
“ “ 5 = 17.84 
The average fruit-weight of this parent pure line is 16.91 grams. 
The variability of the average fruit-sizes of the plants of the 
Red Currant tomato (staminate parent) is very slight and fruits 
from only two plants were weighed. The following average fruit- 
weights were obtained from these plants: 
7-11-2. Plant 1 = .66 gram. 
“ “ 2 = .62 
The average fruit-weight of this parent pure line is .64 gram. 
The F-l hybrid generation of this cross was found to be inter¬ 
mediate in size. The plants possessed the following average 
fruit-weights: 
17-12-2. Plant 1 = 1.90 grams. 
“ “ 2 = 2.48 
“ “ 3 = 2.22 
“ “ 4 = 3.46 
“ “ 5 = 3.76 
The F-l generation average is 2.76 grams. The geometrical 
mean between the weights of the parents is 3.28 grams which is 
only .52 gram more than the actual arithmetical mean of the 
fruit-weights. It is to be also noted that two F-l fruits are 
