April, 1915.] The Inheritance of Size in Tomatoes. 
475 
number of locules. He has taken no weights and from weights 
alone, it appears to the writer, can accurate data be secured to 
show the inheritance of size. 
This problem in genetics was undertaken with tomatoes 
because of their remarkable adaptability to work in heredity 
and because no work had been previously done with them along 
this line; and it was hoped that some contribution might be made 
to our scanty store of knowledge regarding the inheritance of 
quantitative characters—especially the inheritance of size. 
MATERIALS AND METHODS USED. 
Three crosses were made between pure lines of tomatoes in 
the greenhouse of the Ohio State University. The first cross was 
made (1911) between the little red currant tomato, Lycopersicon 
pimpinellifolium, and the yellow pear tomato, Lycopersicon 
lycopersicon (Lycopersicon esculentum). In this cross L. pim¬ 
pinellifolium was used as the staminate parent and L. lycopersicon 
as the carpellate parent. The reverse cross-pollination was made 
many times but fertilization never occurred. The second cross 
was made (1912) between Livingston’s Beauty (carpellate parent) 
and the Yellow Pear (staminate parent). The third cross was 
made (1914) with Livingston’s Beauty as the carpellate parent 
and Bonnie Best as the staminate parent. It is to be noted that 
the first cross was made between species while the second and 
third crosses were made between varieties of L. lycopersicon. 
All of these pure lines with their hybrids have been growing in the 
greenhouse and results have been obtained, but completed data 
is now at hand from only the first cross and this paper will deal 
almost entirely with results obtained from this hybridization. 
These cross-pollinations were made with the utmost care and 
every precaution was taken to provent the presence of any unde¬ 
sired pollen grains. Two unopened flowers of the same age were 
selected—each one on a plant of the pure line to be crossed. A 
capsule of paraffined paper was placed over the staminate bud 
and both ends were tightly filled with cotton so that the entrance 
or escape of pollen was absolutely prevented. A tag was attached 
to the stem of the flower to serve as a means of identification. The 
sepals, petals and stamens of the carpellate bud were carefully 
cut away with sterilized pollinating instruments; the stigma was 
examined with a hand lens to be sure that no pollen grains were 
present, and the gynecium was capsuled and tagged. After three 
or four days both capsules were removed and pollen from the sta¬ 
mens of the staminate flower was transferred upon a sterilized 
glass slide to the stigma of the carpellate flower. Then the 
pollinates! gynecium was capsuled again and left for about a week 
until fertilization had taken place and the young fruit had begun 
to enlarge. All the pollinating instruments were carefully ster¬ 
ilized over an alcohol flame, both before and after they were used. 
