THE BASIS FOR THE IMPROVEMENT OF AMERICAN 



WHEATS. 



INTRODUCTION. 



In 1894 the Division of Vegetable Physiology and Pathology began 

 experiments on an extensive scale to test the comparative rust resist- 

 ance of different varieties of cereals, especially wheat. This work was 

 carried on for three seasons at Garrett Park, Md., Salina, Kans., and 

 Manhattan, Kans., respectively. An account of the results of this 

 work has already been published/ so that it is unnecessary to refer to 

 them in detail here. Suffice it to say that in the course of the work it 

 became apparent that constant rust resistance is not to be obtained 

 among the ordinary bread wheats known at present, though on an 

 average a few such varieties are fairly resistant during a long period 

 of years. By the results obtained it was rendered highly probable 

 that this quality must be bred into a variety either by rigid selection 

 of the most resistant individuals of that variety or by crossing with 

 resistant varieties of other wheat groups and selecting from the result- 

 ant progeny such types as combine in the highest degree the usual 

 qualities of the bread-wheat group with that of rust resistance. 



It was found, moreover, that in regard to other qualities than rust 

 resistance it is not possible to obtain varieties which even approximate 

 perfection, and especially is it rarely, if ever, true that many desara])le 

 qualities are found in the same variety. However rust resistant a cer- 

 tain variety may be, it will usually l)c found lacking in some other 

 ^sential quality, and manifestly the most perfect rust resistance is 

 of no consequence if other essential qualities are absent. As a rule 

 the wheats that are most highly resistant to orange leaf I'ust^ are not 

 varieties of the common bread-wheat group {Trlttcxiii vi(lg((r<') at all. 

 though it by no means follows that they can not be used in bread 

 making. At the same time some of the most valuable sorts for bread 

 Hour, including a number of Russian varieties, rust very badly in 

 certain seasons. Occasionally good qualities may neutralize bad ones 



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'Cereal Rusts of the United States, Bnl. No. 16, Division of Vegetalile Pliysioiogy 

 and Tathology, U. S. Department of Agr., lS!)i>, by M. A. Carleton. 



"■"For descriptions of the two wheat rusts of this country and illustrations of their 

 differences see Bui. No. Ki "I" this Division, a))ove referred to. 



