30 UNIV. OF N. H. AGR. EXPERIMENT STATION [Bulletin 216 



This means that four different plots in various parts of the field received exactly 

 the same treatment. The average of results from these plots eliminates differ- 

 ences due to variations in soil fertility and other local conditions. 



As in previous years, it was found that the use of acid phosphate causes the 

 crop to mature at an earlier date and increases the total yield for the season. 

 In order to determine how this earlier and increased yield is brought about, the 

 plants were measured and the flower clusters counted once a week. The total 

 vegetative growth was obtained by adding together the length of the main 

 shoots and of the side shoots. An increased early growth was found on the 

 plots receiving acid phosphate, especially Plots 4, 5, and 8. 



Counts of the number of clusters per plant showed a close correlation be- 

 tween the total size of the plant and the number of clusters produced at any 

 given date. 



The total yield in pounds up to three representative dates in early, mid- 

 season, and late season, also indicated clearly that the yield of ripe fruit is 

 closely correlated with increase in size and number of flower clusters. 



A test of the effect of commercial fertilizers on the growth and yield of tomato 

 plants in the greenhouse was run during the winter of 1923-24 for comparison 

 with the outdoor results previously recorded. 



The plants of the college strain of Bonny Best variety were set about January 

 1, 1924, 22 by 24 inches apart in a ground bed, into which a three-inch covering 

 of well-rotted stable manure had been spaded. Each plot consisted of one row 

 of eight plants, and was separated from adjoining plots by boards sunk into the 

 ground. To overcome errors due to differences in temperature and light, each 

 treatment was repeated upon four different plots in different parts of the house. 



The rate of ripening under greenhouse conditions was found to be apparently 

 affected chiefly by the temperature, and little difference was found between the 

 different plots. As in the outdoor experiment, the highest yield was obtained 

 from the acid phosphate plots. The use of potash alone gave a slight increase 

 in yield, but potash combined with acid phosphate gave a lower yield than acid 

 phosphate alone. This is in accord with the results obtained in the field plots. 



Plant Breeding — Tomatoes. 



In 1922 thirty-two selections of high-yielding plants and thirty-two selections 

 of low-yielding plants were made by J. R. Hepler from a strain of Bonny Best 

 variety of tomatoes which had been closely inbred in the greenhouse for six 

 years. During the summer of 1924 the selections were again grown in the gar- 

 dens and, as has been recorded in previous years, little difference was found in 

 the average yield of the strains. The plants selected for earUness and high 

 yield ripened two pounds of fruit by September 18, and a total of 12.9 pounds 

 for the season. The low 3'ielding and late strain of tomatoes ripened 1.9 

 pounds of fruit by September 18 and a total of 15.1 pounds for the season. 

 There is a good deal of variation between the different plants of each strain, and 

 apparently the variations upon which the original selections were based were 

 somatic rather than of a heritable nature. 



In connection with these strain tests twelve to twenty plants each of a num- 

 ber of the standard varieties of tomatoes were grown and the yield recorded. 



