RECIPROCAL BREEDING IN TOMATOES 



Study Made in Order to Compare Relative Values of the Two Directions of the 



Cross — Certain Characters in Plants Correlated with Weight 



and Size of Fruits 



Byron D. Halsted 



Botanist, K. J. College Agriculttiral Experiment Station, New Brunswick, N. J. 



FOR THE purpose of studying; the 

 relative values of the two direc- 

 tions of the. cross in reciprocal 

 breeding two kinds of tomatoes 

 were selected that had at least four 

 contrasting characters. The Dandy 

 Dwarf variety (158) with its dwarf 

 plants, having yellow foliage and coarse 

 leaves and red fruits was combined 

 with the Yellow Cherry (183), a stan- 

 dard sort with green foliage and fine 

 leaves and yellow fruit. The union in 

 two opposite directions was between 

 but one plant of each kind, that is, the 

 plant a-a, Dandy Dwarf, was bred upon 



the plant b jj~ representing the Yellow 



Cherry, and the reciprocal was between 



the same two plants, namely — 



a. 



During the season of 1917 the study 

 was mainly between the two sets of 

 plants of the second generation, but, 

 as is the general rule, a small niunber 

 of Fi plants as well as of the two par- 

 ental kinds were grown. 



The Dandy Dwarf is a fair average 

 of the kinds that are of low stature 

 with short branches and thickly-set 

 leaves. It bears red fruits that are 

 broader than long and weigh near 24 

 grams. The Yellow Cherry is a tall- 

 growing variety, with green foliage, 

 fine leaves and yellow fruits of near a 

 fourth (5.4 gr.) of the weight of the 

 Dandy Dwarf, and not far from a 

 half as long and broad as the red 

 fruits of its breeding mate, as shown 

 below : 



The Fi plants were all standard, 

 green, fine, red and with the following 

 fruit-weights and sizes : 



1. Dandy Dwarf upon 

 Yellow Cherry FI.. 



2. Yellow Cherry upon 

 Dandy Dwarf FI.. 



Gr. 

 16.29 



16.47 



Afm. Mm. 

 25.99 32.80 

 28.42 34.02 



The Fi plants, with Yellow Cherry 

 as the seed parent yield lighter and 

 smaller fruits than the reciprocal. The 

 greatest difference is in the length, 

 namely 9.35%. In other words, the 

 fruit characters of the seed parent are 

 approached in both unions. 



Records of each F2 plant were taken 

 for the following characters, namely, 

 type of plant (whether standard or 

 dwarf) the color of foliage (whether 

 green or yellow) the kind of leaves 

 (whether fine or coarse "potato- 

 leaved") color of fruit, (whether red or 

 yellow). Five fruits from each plant 

 were weighed singly and measured for 

 both length and width. The fruits 

 were taken at random when fully ripe, 

 and the picking and measuring were 

 done by a student who had no knowl- 

 edge of the purpose the records were 

 afterwards to serve. 



From the records 126 F2 plants have 

 been taken from each of the two sets. 

 In one of the crosses this was the total 

 number that had each of the several 

 items in full and without flaw. In 

 the reciprocal the first 126 plants with 

 complete record were used. 



Table I shows the results for the four 



169 



