DEVELOPMENT OF WILT-RESISTANT TOMATOES. 9 
its parent variety in degree of resistance transmitted. In another 
similar case, 30 apparently resistant plants of Earliana and 118 of 
Bonny Best, the only wilt-free plants found in two fields of 6 acres 
each, failed to transmit more than average resistance for their re- 
spective varieties. 
Selections from varieties that transmit resistance to their individual 
plants somewhat diversely, such as the Stone, Greater Baltimore, and 
Merveille des Marches, not infrequently excel their parents in the 
transmission of wilt resistance. 
BEHAVIOR OF RESISTANT VARIETIES. 
Although none of the varieties of wilt-resistant tomatoes devel- 
oped by the writer are immune to wilt, they are highly resistant to 
it. In repeated tests on heavily wilt-infested soils they have main- 
tained a high degree of resistance. A more important possession, 
however, is their high yield and the superior quality of their fruit 
when grown on wilt-infested soil. As they have been selected from 
the best commercial varieties, primarily for yield and quality of 
fruit and secondarily for wilt resistance, they possess the high yield- 
ing power of the parent varieties in addition to resistance and are 
therefore equal to them on wilt-free soil and far superior to them 
on wilt-infested soil. The behavior of two of these varieties is 
illustrated in Plates VI and VII. . Plate VI, figure 1, shows the 
Brimmer, a very popular variety in the South, while figure 2 is the 
Xorton. They were grown in opposite ends of the same rows near 
Richmond, Va. The Brimmer was absolutely destroyed by wilt, 
while the Norton produced an excellent crop of fruit. In Plate VII, 
row 1 is the Greater Baltimore and row 2 the Arlington, a selec- 
tion from the Greater Baltimore. Although planted at the same 
time and given identical cultural conditions, the Greater Baltimore 
was completely destroyed, while the Arlington was apparently free 
from wilt and produced a good crop of fruit. 
EFFECT OF CONTINUOUS SELECTION. 
A tomato plant usually transmits to its immediate offspring as 
much wilt resistance as can be developed from it by subsequent 
selection. In a very small percentage of plants tested for wilt re- 
sistance by the progeny-row method, increased resistance has been 
obtained in the second selection, but no higher resistance has resulted 
from a continuation of this process. As crossing occasionally occurs 
in the tomato, the hybrid condition resulting from it may account 
for the exceptions noted. 
The effect of continuous selection from two wilt-resistant varieties 
developed at Washington, D. C, and from one developed in Louisiana 
are shown in Table 2. The tests were made in rows of 16 plants 
68713°— 22 2, 
