BUEEAU OF PLANT INDUSTKY. • 147 



These results follow when the seed is injured b}' normal weather 

 conditions as well as when injured by subjection to moisture, freez- 

 ing, and thawing. Mechanical mutilations of kernels similar to the 

 chipping, cracking, and breaking that to some extent take place in 

 shellers and planters reduce the productiveness of the plants that 

 grow from such kernels. 



The point of value that has been established is that, independent 

 of heredity and independent of germinability, any injury to dormant 

 seed corn reduces the power of such seed to produce a good crop. 

 Seed corn of 100 per cent germination, laboriously secured from 

 injured seed by individual-ear germination tests, is less productive 

 than seed that matured well and was so cared for as to make individ- 

 ual-ear testing unnecessary. 



Tests under the same environmental conditions of widely dissimi- 

 lar varieties have brought out the value in long-season districts of 

 making plantings at different periods and using at least two varieties 

 of different seasonal requirements in order better to meet the exi- 

 gencies of the season and to insure a crop. 



GROWING GRAIN SORGHUMS. 



The grain-sorghum area increased from 3,944,000 acres in 1916 

 to 5,153,000 acres in 1917, or more than 30 per cent. Production in- 

 creased from 53,858,000 to 75,866,000 bushels, or over 40 per cent. 

 This largel}^ increased quantity of grain was consumed through 

 the ordinary channels without any undue drop in price. Farmers 

 report excellent results from Dwarf milo and Dawn kafir, the vari- 

 eties bred and distributed by the department, and the demand for 

 seed increases. In Arizona and California Dwarf milo is grown suc- 

 cessfully on irrigated land after barley is harvested, thus enabling 

 the farmer to grow two grain crops on the same land in one year. 



BROOM-CORN PRODUCTION. 



Under the stimulus of high prices an increased acreage of broom 

 corn was grown in 1917. Drought reduced the yield and quality and 

 resulted in the highest prices known for many years. The produc- 

 tion of this crop has been extended into new districts of southern 

 Texas, especially under irrigation in the Rio Grande Valley. 



SUGAR-BEET GROWING. 



At the beginning of the fiscal year 98 beet-sugar mills w^ere stand- 

 ing and equipped for making sugar. Two were built during the year, 

 making a total of 100. Several new mills are in process of construc- 

 tion, some of which will be ready to handle the 1918 crop of beets. 



Among the factors that are retarding sugar-mill construction are 

 scarcity of material and scarcity of sugar-beet seed. These retarding 

 influences are gradually being overcome, and the indications are for 

 a marked advance in sugar-mill construction and in the development 

 of new sugar-beet areas. Practically none of the existing mills were' 

 able to operate for a normal period of 100 days last year, for lack of 

 raw material. 



The domestic production of sugar-beet seed last year amounted to 

 nearly 40 per cent of this year's planting requirement, and the quan- 



