ANNUAL REPORT, 1939 79 



to vary from 2 to 7 inches, with an average depth of 3.6 inches. Roots originally 

 planted 4 inches deep were found to vary as did those planted 2 inches, the 

 average depth being 4.5 inches. The average depth of roots planted 6 and 8 

 inches deep was 3.9 and 4.5 inches respectively. While there are some differences 

 in the average levels, it might be said that all the asparagus plants formed at the 

 level they preferred for the soil in which they were planted, which is a Merrimac 

 fine sandy loam underlaid with coarse gravel. The information concerning the 

 levels to which asparagus crowns grow, together with yields and stand counts, 

 is being prepared for presentation before the American Society for Horticultural 

 Science. 



The height-of-cutting records continue to show that when asparagus tips are 

 cut the yield will be less than when spears are cut with 8 inches of green. Almost 

 i5 percent more 4-inch spears per plant have been produced than 8-inch, but the 

 yield in pounds is much less for the nine years the plots have been harvested. 

 Cutting spears with 12 inches of green has not reduced the yield in pounds of 

 asparagus although it reduces the number of spears. 



It would seem from the results of this experiment that the best returns from 

 an asparagus bed can be obtained by cutting the spears with 8 inches of green. 

 However, there seems to be no danger of injuring the bed by producing long 

 asparagus, even up to 12 inches. 



It appears from the two sets of asparagus records that ha\e been kept for seven 

 and nine full cuttings seasons that the peak of production comes in the third year. 



Trellis Tomato Experiments. (Robert E. Young and Paul W. Dempsey, 

 Waltham; Alden P. Tuttle, Amherst.) This past season was a very dry one, and 

 it is of interest to note that pruning tomatoes to a single stem increased the per- 

 centage of cracking of fruit. The plot that had potted plants pruned to a single 

 stem produced the largest early yield and the greatest total yield. The plots that 

 produced notably low yields were those without fertilizer, those with plants not 

 trellised, and those without manure. The plants not pruned or trellised pro- 

 duced only one-third the early yield of the best trellised plot. These untrellised 

 plants produced fruit that had the least cracking. Additional inigation also 

 greatly reduced cracking. The work on trellised tomatoes has been concluded. 



Vegetable Breeding for Improvement of Quality. (Robert E. Young, Waltham.) 



Lettuce, New York Type. (In cooperation with United States Department of 

 Agriculture.) Approximately 10,000 plants were grown last season in the search 

 for a better adapted lettuce. Of these plants, the four single-plant selections 

 made from a new hybrid were outstanding for heading, color, and resistance to 

 tipburn. These new types are hybrids similar to the Cosberg, which is a light 

 yellow variety, except that they are dark green in color and produce a better head. 



During the past season the aster yellows disease was quite severe and wide- 

 spread, affecting lettuce all over the northeastern United States. In other seasons 

 from 10 to 25 percent of the selected plants have become infected with aster 

 yellows and have been lost, since the diseased plants do not produce seed. This 

 past year approximately 85 percent of the selected plants became infected with 

 the disease, thus causing a loss of the most important breeding stock. Whether 

 the increase in the extent of the disease is due to weather, or is a natural increase 

 which will persist in future years, remains to be determined. Certainly some 

 method of protection must be found if a breeding program is to continue. 



The selections that have been grown for a number of seasons continue to be 

 superior to commercial varieties. However, they are susceptible to the same 

 trouble as the commercial varieties but to a lesser degree. 



Greenhouse Lettuce. The first generation of a cross between Bel-May and 

 Cheshunt Giant was produced in the greenhouse. Although both of these varieties 



