B. P. I.— 606. 



BREEDING DROUGHT-RESISTANT FORAGE PLANTS 

 FOR THE GREAT PLAINS AREA. 



INTRODUCTION. 



This paper describes the results so far attained in breeding im- 

 proved strains of alfalfa, sorgo, millet, smooth brome-grass, and 

 other forage plants adapted to the semiarid conditions of the elevated 

 region lying between the ninety-eighth meridian and the Rocky 

 Mountains. While the work with none of these crop plants has 

 reached completion, it is considered desirable to publish at this time 

 a description of the objects, methods, and preliminary results. 



In this plant-breeding work, as in all other investigations bearing 

 upon dry-land agriculture that are carried on by the Bureau of Plant 

 Industry, it is intended to make the results applicable to the whole 

 territory in which similar climatic conditions exist. By conducting 

 the work simultaneously and with the same methods at different 

 stations, comparable results are expected. The working out of this 

 plan should afford a much safer basis for the establishment of broad 

 principles in drought-resistance breeding than could be attained by 

 any strictly local work. Although the actual breeding is at present 

 confined to only two of the dry-land stations, these are representative 

 of a considerable portion of the Great Plains. 



At both of these stations the Office of Forage-Crop Investigations 

 is engaged in testing varieties of the forage plants that are believed 

 to be adapted to the climatic conditions of the region. The drought- 

 resistant plant breeding is conducted in cooperation with these 

 variety tests, which not only afford material for the selection of 

 resistant individuals, but give an excellent opportunity for com- 

 paring the drought resistance of the new strains developed with that 

 of a large number of existing varieties of the same crops. 



OBJECTS SOUGHT. 



To make dry-land farming in a semiarid region like the Great 



Plains a reasonably safe enterprise, drought-resistant crops must be 



grown. Most of the varieties of crop plants that have heretofore 



been used in this region have originated in countries of abundant 



196 7 



