BUREAU OF PLANT INDUSTRY. 457 



Preliminary experiments in the study of tuber formation of pota- 

 toes indicate that deep planting has little influence on the number of 

 tubers, but has considerable influence on their development. The 

 most important effect of deep planting is apparent in the lengthening 

 of the internodes of the plant below the surface of the soil. 



The test to determine the region from which seed for best results in 

 the trucking region can be obtained has been continued. The work of 

 the year confirms the idea that seed from the North and from high 

 altitudes of the Southern States is more productive and earlier than 

 seed grown in the local trucking region. 



Tests to determine the comparative value of germinated and unger- 

 minated potatoes for seed made during one season only with northern- 

 grown seed were negative in their results. 



The present commercial potato industry in the trucking region is 

 based entirely on varieties not especially developed for the industry 

 or the locality. The potato industry in the irrigated section of the 

 country has been developed in exactly the same way. In order to 

 make these industries what they are capable of being made, sorts 

 especially suited to the system of cultivation and the particular cli- 

 matic conditions of the region should be developed. In order that the 

 greatest value may come from this collection, it should not only be 

 tested at the three points now under observation, but the test should 

 be extended to Florida, to some point in Louisiana or Texas, and to 

 California. 



Saveet-potato investigations. — The growing, storage, and desicca- 

 tion work on sweet potatoes has been continued. Feeding tests are 

 being conducted in cooperation witli the Bureau of Animal Industry 

 with desiccated products, and the manuscript for a bulletin on stor- 

 age of the crop has been prepared. The cooperative studies on the 

 physiological behavior of sweet potatoes in storage has been con- 

 tinued. Arrangements are being made with the experiment stations 

 of Alabama and Mississippi to conduct cooperative storage tests. 

 The problem of properly housing and storing this crop is of great 

 economic importance in the South. It is planned to extend activities 

 in connection with this industry, so as to determine the best methods 

 of storing, shipping, and marketing. 



Celery inves'ogations. — Attempts to place large quantities of 

 celery in cold storage in various parts of the country have developed 

 conditions which make it necessary to carefully investigate not only 

 the field handling of celery, in order to produce a clean, disease-free 

 crop, but to determine the best type of crate and the method of pack- 

 ing, transporting, and storing the crop, in order to meet the market 

 requirements. The success of the storage industry with celery is 

 dependent upon the solution of these problems. 



Onion investigations. — The Denia onion industry has progressed 

 far enough to demonstrate the possibility of a satisfactory American 

 production of this type of onion. The one drawback to the Denia 

 and Bermuda onion industries is the question of seed supply. At 

 present Denia seed comes from Spain and the Bermuda from the 

 Teneriffe Islands. The unreliability of the supply places the Ameri- 

 can industries on a very hazardous basis. Some preliminary work 

 has been done to determine the possibility of growing these types of 

 onion seed in America. 



