BUREAU OF PLANT INDUSTRY. 185 



crease of about 20 per cent over 1919, and owing to better seasonal 

 conditions the outlook for a good jaeld of fiber is very much better. 



Semicommercial test plats of pedigreed strains developed by five 

 to ten years of selection made an excellent showing in commercial 

 flax fields in eastern Michigan in 1919. The increased vigor of the 

 plants, giving an increased yield of fiber and fiber of better quality, 

 was plainly marked. 



Efforts are being made by means of increase plats in IVIichigan 

 and AV^isconsin in summer, and in Porto Rico in winter, to secure 

 increased supplies of these improved strains. 



The plant-breeding work Avith flax is being continued by direct 

 selection and also b}- cross-pollination, w^th a view to securing 

 further improved strains. ISIarked differences in the vigor of plants, 

 height, resistance to lodging, resistance to disease, and in yield and 

 character of fiber are secured without great difficulty, but the in- 

 crease of seed of improved strains is necessarily slow. 



Fiber flax in this country is less affected by diseases than seed flax, 

 but there has been some loss from wilt, rust, and canker. A study 

 is being made of the diseases, and preliminary w'ork is being started 

 with a view to the development of disease-resistant strains. 



PROMISING NEW VEGETABLE CROPS. 



The dasheen continues to grow in importance in our Southern 

 States; wdiile in 1919 the total estimated area planted to dasheens 

 was 150 acres, in 1920 the acreage exceeds 400, individual plantings 

 being increased in size. One large stock i-aiser in Florida has planted 

 this jTar 160 acres, he having found in 1919 th;U the dasheen made 

 a valuable stock feed. Over 1,600 distributions of dasheens were 

 made to experimenters in 1920. Most of this crop is used where 

 grown for human food, stock feed, and seed for planting. Larger 

 commercial shipments are being made each year to northern markets. 

 Two carload shipments from the 1919 crop were sent north, wdiile 

 there Avas only one such shipment from the 1918 crop. New ways of . 

 using the dasheen have been developed, and one manufacturer of po- 

 tato chips (in Washington, D. C.) has become deeply interested in the 

 dasheen for the production of chips. These look very much like the 

 " Saratoga " chips made from j^otatoes, but are superior to them in 

 quality. This manufacturer is firmly convinced of the potential com- 

 mercial value of dasheen chips and has arranged to put them on the 

 market when a supply of dasheen tubers becomes available this fall. 



Tropical yciTn {Dioscorea sp.). — The prohibition of further com- 

 mercial importations of tropical yams, on account of the danger of 

 the introduction of a very injurious root Aveevil, resulted in a de- 

 mand for the production of these yams in the Southern States. Pre- 

 vious tests had shown that some varieties were ada])ted to southern 

 Florida, and experiments looking toward the more rai)id propagation 

 of those were at once Ijegun. Additional varieties have l)oen secured 

 from the Tropics and will be tested to determine their adaptability 

 to the climatic conditions of Florida. Plantings on a conmiercial 

 scale have been made by a growci- at Brooksville, Fla., who has .5 

 acres in yams this year. The establishment of a tropical yam indus- 

 try is apparently assured. The yam yields heavily when given proper 

 conditions, and as it can be grown in many situations where neither 



24435— AGB 1920 13 



