ANNUAL REPORT, 1943-44 55 



this year. Of the 50 best plants in 1943, half had increased their yield while the 

 others yielded less than previously. 



The rust disease which was so general in 1942, and had been increasing for the 

 last few 3'ears, failed to show up even on the most susceptible plants. 



Vegetable Breeding for Improvement of Quality. (Robert E. Young, Wal- 

 tham.) During the year breeding work has been conducted with greenhouse 

 cucumber. Summer Pascal celery, rutabaga, greenhouse lettuce, New York type 

 lettuce, broccoli, carrot, and tomato. While progress has been made in develop- 

 ing strains of broccoli, carrot, and tomato better adapted locally, it is insufficient 

 to justify detailed discussion. 



Greenhouse Cucumber. The work of breeding a greenhouse cucumber has been 

 projected along two lines. The first method has been to self-pollinate the best 

 strains or varieties obtained from local growers. These strains originally varied 

 considerably because the seed had always been mass-produced. Selfing has 

 made them sufficiently uniform for extended trials with the growers. 



In the second method of breeding, hybrids made by crossing these selfed lines 

 were used. Yield trials with this material have been restricted by lack of green- 

 house space. In the spring of 1943 the average yield of four hybrids over their 

 respective parents was 11 percent. With better seed lines in 1944, the increase 

 was 30 percent. Certain combinations of selfed lines were much better than 

 others, such as hybrid M x A which was 35 percent better than the parents; 

 A X H was 7 percent better; and H x W, 50 percent. 



While it will take time to determine the proper combinations necessary for 

 best yields for spring and fall, and under different types of pruning and training, 

 the hybrid vigor is such as to make it desirable to place this material in the hands 

 of growers for further testing. Moreover, the hybrids have produced an increase 

 not only in yield but also in the percentage of No. 1 fruit, which is very impor- 

 tant. To determine the best methods of producing hybrid seed, and the cost, has 

 now become a part of this investigational work. 



Greenhouse Lettuce. The crosses of Bel May X Cheshunt Early Giant were 

 judged sufficiently uniform to be given a trial by growers before final fixing. 

 The new variety has been named Waltham Early Forcing. In comparison with 

 Bel-May it grows faster, has a darker green color, better development of the 

 leaves on the bottom, and bolts to seed more slowly. Waltham Early Forcing 

 plants are smaller than Bel-May, and the overlap of the leaves of the head is 

 not so good. 



Tests are now being conducted by growers in greenhouse and hotbed. The 

 results of these tests will be used to determine whether the variety has sufficient 

 merit to justify further work. 



Lettuce, New York Type. (Cooperation with U. S. Bureau of Plant Industry.) 

 The work with this crop has progressed to the point where two of the selections 

 are ready for trial by growers. The first strain is one that has been selected for 

 several years. It came originally from Dr. Whittaker of the U. S. Department 

 of Agriculture, La Jolla, Calif., and is the same hybrid material from which Great 

 Lakes was selected. Under our conditions the selection produced 90 percent 

 marketable heads, as compared with 67 for the Great Lakes. There are some 

 differences in the shape of head and character of the leaf but, in general, it re- 

 sembles Great Lakes. 



The second selection being made ready for trial is one from segregating material 

 provided by Dr. Thompson of the U. S. Bureau of Plant Industry, Beltsville, 



