April, 1915.] The Inheritance of Size in Tomatoes. 
479 
The experiments of Phillips in 1912 (40) upon the inheritance 
of size in ducks were more extensive than the work of Castle or 
Ghigi. He crossed a Mallard with a Rouen duck and found that 
the F-l birds were intermediate in size as compared with the 
parents. Segregation was present in the F-2 generation. Phil¬ 
lips concludes, “The amplitude of variation of the F-2 fowls is 
greater than that of the F-l fowls but does not extend beyond the 
nearer limit of the respective grandparental races.” 
Nilsson-Ehle (1908) showed how the Mendelian notation for 
the inheritance of qualitative characters might be used as a basis 
for the explanation of the inheritance of quantitative characters. 
East in 1910 (14) in ignorance of Nilsson-Ehle’s 1908 paper, 
developed a similar theory and showed how certain data on the 
inheritance of the number of rows of grains on an ear of maize 
could thus be analyzed. 
Emerson in 1910 (19) issued a paper on the inheritance of 
quantitative characters in Cucurbita pepo, Phaseolus vulgaris and 
Zea mays. He showed segregation of size factors but offered no 
Mendelian explanation. 
Johannsen (32) crossed two lines of beans and worked with the 
inheritance of length and breadth. He found the F-l generation 
intermediate between the parent biotypes. The F-l beans were 
no more variable than the parents but no definite conclusions can 
be drawn from this fact as only a limited number were grown. 
The F-2 and F-3 generations showed greatly increased variability 
over that of the parent biotypes. The length of the parent beans 
differed widely from each other. Neither the F-l nor F-2 genera¬ 
tion reached the extremes in length of the parent biotypes but the 
F-3 generation did reach those extremes. The breadth of the 
parent beans were very similar. The F-2 generation exceeded in 
breadth the extremes of the parent biotypes, while the F-3 genera¬ 
tion more widely overlapped those extremes. 
Belling in 1912 (1 and 2) crossed two widely different bean 
varieties. The F-l generation exceeded in size of seed and plant 
either of the parents. The F-2 generation showed marked 
variability. 
East in 1913 (13) worked upon the corolla length of Nicotiana 
and found the F-l hybrid corolla length to be the geometrical 
mean between the parent lengths. The F-2 generation showed 
greater variability than the F-l generation. 
Groth in 1912-13 (26, 27, 28 and 29) conducted extensive 
experiments upon the inheritance of tomato seedlings, leaves and 
fruits. He worked with linear dimensions and found the F-l 
fruit to be the geometrical mean between the parental dimensions. 
Marked segregation of size occurred in the F-2 generation. His 
Mendelian explanation of the results is very complicated and will 
be discussed later in this paper. 
