COLORS IN VEGETABLE FRUITS 



Tomato, Eggplant and Pepper, Belonging to the Same Family, Have Similar Groups 

 of Simple Color Factors -Combinations Are Easy to Make 

 BvROx D. Halsted 

 Botanical Department, New Jersey Experiment Station, New Brunswick, N. J. 



THE maturity colors of the fruits 

 of tomato, pepper, cj^p^plant, as 

 well as other vegetable fruits, 

 lend themselves well to a study of their 

 inheritance. 



In the tomato fruit, the skin and the 

 flesh may be considered separately at 

 the outset. The skin is either trans- 

 parent or is colored with an orange pig- 

 ment. These two types are easily dis- 

 tinguished by removing a portion of the 

 skin, scraping it clean of all adhering 

 pulp and holding it u]) toward the sun or 

 other light, or laying it upon white 

 paper. 



The flesh is either pink-purple or 

 lemon-yellow, and this fact needs no 

 further demonstration than that of 

 making slices through the mature fruit. 



It is not claimed that there are no 

 variations, but the above statements 

 hold in a general way and serve as a 

 basis for the more detailed consideration 

 that follows. 



As all tomato fruits consist of the 

 interior and the skin surrounding it, and 

 as there are two colors for both flesh and 

 skin, it is clear that the possible com- 

 binations are four, namely: (1) lemon 

 flesh and colorless skin, (2) lemon flesh 

 and orange skin, (3) red flesh and color- 

 less skin, and (4) red flesh and orange 

 skin. These four combinations con- 

 stitute four fi^uit colors in the order 

 above given as follows: (1) lemon, (2) 

 orange, (3) pink, and (4) red. All of 

 these color-terms are only approximate, 

 but they will serve for the present i^ur- 

 pose and have the advantage of being 

 short and leading to no confusion. 



In breeding it is found that the pink 

 flesh is dominant over the lemon flesh, 

 and the orange skin is dominant over 

 the colorless skin. It follows that the 

 varieties of lemon-colored tomatoes are 

 doubly recessive, and when l)rcd wilhiii 

 18 



the group are not expected to produce 

 any other color of fruit. It, by the way, 

 is a group of kinds that is rarely repre- 

 sented in cultivation excepting where a 

 large assortment is sought for some 

 special purpose. The reason for this 

 general exclusion of the lemon tomatoes 

 is not within the scope of this paper to 

 consider. The orange-colored group of 

 varieties perhaps stands second in repre- 

 sentatives in the fields and gardens and 

 is particularly noticeable among the 

 smaller types, like "pear," "plum," 

 and "cherry" sorts used for preserving, 

 pickling, etc. In breeding it is to be 

 borne in mind that the two characters 

 combined are the lemon flesh and the 

 orange skin, in other words a recessive 

 for the former and a dominant for the 

 latter, and within the group the oft'spring 

 would be expected to be constant in 

 fruit color. 



BREEDING TWO GROUPS 



Let the two above groups be bred 

 together and it is clear that the flesh will 

 remain the same and the only variation 

 will be in the skin, for here a dominant 

 (orange) is combined with a recessive 

 (colorless), and according to rule in the 

 Fi all plants will bear orange fniits, and 

 in the F2 three-fourths of the plants will 

 bear orange fruits and one-fourth lemon 

 fruits. In the third group the fruits are 

 pink (sometimes called purple, as the 

 Ponderosa) and therefore have a domi- 

 nant flesh color and a recessive skin 

 color. This group seems to stand third 

 on the list for popularity among the 

 growers of the fruit. When bred with- 

 in its own group, no change need be 

 expected so far as fruit color is con- 

 cerned. Let it be bred with the first 

 group, the lemon-fruited sorts, and then 

 there is a combination of the flesh colors 

 with no di\-ersitv in skin. Here the 



