16 MASS. EXPERIMENT STATION BULLETIN 419 



Table 4. Effect of Two Systems of Training Plants 

 ON the Yield of Trellis Tomatoes. 



^^'althaITl Amherst Combined Crop 

 Treatment ■ ■ ■ 



Early Total Early Total Early 



Yield per Acre, Pounds 



Single Stem 16,446 45,360 7,748 53,311 13,097 49,335 



Double Stem... . 11,796 41,845 8,289 47,487 10,042 44,666 



Yield per Plan!, Pounds 



Single Stem 1.52 4.20 .63 4.93 1.07 4.56 



Double Stcnu. . . 1.96 6.97 .90 7.91 1.43 7.44 



Only the lower cluster of fruit on the plant was included in the early yield, 

 and each plant has only one such cluster regardless of how pruned. Branching 

 for the two stems usually took place near or above this first cluster. Therefore, 

 the single-stem plants set 10,000 to the acre had a larger number of clusters of 

 early fruit than the two-stem plants set 6,200 to the acre. When considered on 

 the basis of production per plant, those pruned to two stems had the highest 

 early and total yield. 



The method of training the plants made very little difference in the size of the 

 fruit. The larger >'ield of early fruit as a result of pruning to a single stem is 

 important, but growers should not lose sight of the fact that a greater number of 

 plants per acre is necessary. 



It would seem that a grower located on high-priced land should provide him- 

 self with adequate plant-growing facilities and train the plants to a single stem, 

 since this method returns the largest profit per acre. Growers whose land is 

 not so valuable could train the plants to two stems and get more fruit from each 

 thousand plants grown. 



With these facts in mind, each grower can survey his land and plant-growing 

 facilities and decide which training method best suits him. 



Pruning 



After the trellis is up, the strings are on the wire, and the plants have started 

 to put out new growth, it is time to begin pruning. Figure 6 shows a plant at 

 the proper stage to start pruning. 



The tomato plant has one central shoot or leader. At each joint or leaf, a shoot 

 comes out and if these are allowed to grow, the plant will produce a large bush 

 with many stems which cannot be tied up or supported on trellis. If the plants 

 are to be pruned to a single stem, onlj- the central shoot is allowed to grow. The 

 side shoots, or suckers as they are sometimes called, that appear at each joint 

 are removed when they become 2 to 4 inches long. Pruning delayed until the 

 side shoots are 6 inches long reduces the vigor of the plant. 



If the plant is to be pruned to two stems, the central shoot and one side shoot 

 are allowed to grow and the remainder are removed. One side shoot will be 

 found more prominent and vigorous than the others, and if this is not over 10 

 inches from the ground it is the best one to leave. 



It is necessary to prune the plants, and twist the stems around the string, 

 every week during the early period of rapid growth. 



