CEREAL IMPROVEMENT HYBRIDIZATION 227 



239. Work of the United States Department of Agri- 

 culture. Investigations of cereals by the United States 

 Department of Agriculture have been heretofore largely 

 a study of cereal groups and standard varieties and the 

 introduction and acclimatization of adapted foreign 

 varieties. A considerable amount of breeding work, 

 however, has been done. Wheat breeding began in 1898, 

 oat breeding about 1902, and barley breeding about 1904, 

 and very recently some breeding experiments with rye 

 have been started. With many 

 of the important practical results 

 the breeders are not yet satisfied, 

 but much gain has been made in 

 the addition of earliness in hard 

 winter wheats and of rust-resist- 

 ance in spring wheats. Over 

 1000 hybrid selections from about 

 500 original wheat crosses have 

 been under observation at one 

 time or another. For rust-resist- 

 ance, Khapli emmer, Persian 

 Black wheat, einkorn, and sev- 

 eral durums have been found, so 

 far, to be the best parents, but 

 still better ones are sought. For 

 earliness in winter wheats, Zim- 

 merman has appeared to be a 

 good parent (Figs. 67-70). 



240. Examples of United States 

 hybrids. Arlington Awnless barley is an interesting 

 result of one of the barley hybrids. In 1904 a cross of 

 Tennessee winter (six-row) with Arabian Black (two- 

 row) was made. In the third generation a peculiar 



FIG. 71. Spike and spike- 

 lets of Arlington Awn- 

 less barley. 



