DEVELOPMENT OF WILT-RESISTANT TOMATOES. 11 



developed by Edgerton and by Bain and Essary have shown approxi- 

 mately the same resistance at Washington as in Louisiana and Ten- 

 nessee. The permanence of wilt resistance would therefore seem to 

 depend on the prevention of crossing with susceptible varieties. 



RESULTS OF FIELD TESTS. 



Field tests 5 of the varieties of tomatoes described in this bulletin 

 have been made on an extensive scale in Maryland, Delaware, Virginia, 

 Georgia, and Alabama and on a smaller scale in 19 other States. In 

 no case 6 have these varieties failed to maintain a high degree of re- 

 sistance to wilt. Numerous reports from pathologists, horticulturists, 

 canners, truckers, and growers of home gardens show that the yield 

 and quality of fruit have usually been much better than from other 

 varieties. On heavily wilt-infested soils the superiority of the re- 

 sistant varieties has often been very great ; in fact, in many fields in 

 which it has been impossible to grow tomatoes for years on account of 

 wilt these varieties have produced a heavy crop of fruit. 



Wilt resistance in these tests has not usually been reported on a 

 percentage basis by tomato growers, as they are not always able to dis- 

 tinguish wilt from blight or other diseases. Moreover, they are in- 

 terested in general results more than in percentages, and they there- 

 fore usually report by means of such general statements as these : 



They were beauties and splendid yielders. They surely had a fair chance 

 and proved to be nonwilt. When one-half of our patch was dead, they were 

 green and the ground lay full of nice tomatoes. 



Up to date none of the plants of yours have shown any sign of wilt, whereas 

 all other plants of tomatoes I had wilted badly, being entirely destroyed long ago. 



Throughout the entire county the tomato crop was a complete failure except 

 the ones that used the wilt-resistant seed. 



They were all heavy bearers and none of them wilted. 



Your tomatoes were grown in four different parts of a 10-acre field of Stone 

 tomatoes. The fruit and quality were better than the Stone tomatoes. 



The Norton gave at least double the yield of the Greater Baltimore. 



If we could buy the kind of seed you sent us last spring in sufficient quantities 

 to plant our entire crop, it would double our yield, even if the vines were 

 slightly affected by the wilt. 



B Many of these tests were arranged with, commercial tomato growers and growers of 

 home gardens by plant pathologists, botanists, and horticulturists of the State agricul- 

 tural experiment stations and by members of the Office of Extension Work South in the 

 States Relations Seryice. Much- credit should be given to these cooperators, especially 

 to C. E. Temple, Thomas F. Manns,, J. M. LeCato, F. D. Fromme, George L. Peltier, 

 G. M. Armstrong, and Ola Powell, who have conducted extensive tests. 



6 One apparent exception to this statement was made by McClintock to the Plant- 

 Disease Survey when he reported : " All so-called resistant strains which we were able 

 to obtain were tested in badly infested soils in 1919 and none proved sufficiently resistant 

 to grow and bear throughout the summer." As these results are so different from those 

 reported by McClintock for Georgia the previous year and Dy others for several years 

 and from several thousand reports received from various localities in Georgia and other 

 States, the writer is of the opinion that wilt was not the sole cause of these unfavorable 

 results. 



