528 



SCIENCE 



[N. S. Vol. L. No. 1301 



SPECIAL ARTICLES 



GERMINATING FRESHLY HARVESTED WINTER 

 WHEAT 



Frequently only a small percentage of 

 freshly harvested winter wheat germinates 

 readily under the conditions ordinarily used 

 in making the germination tests even though 

 it would germinate well under these same 

 conditions a few weeks later. In sections of 

 the country where farmers depend upon wheat 

 from the current crop for the fall sowing the 

 poor germination secured with the fresh grain 

 has made it difficult for seed analysts to give 

 accurate information as to the quality of 

 winter wheat offered for seed in time for this 

 information to be of service. 



In a recent investigation by the Seed Test- 

 ing Laboratories of the United States Depart- 

 ment of Agriculture it has been found that 

 the difficulty described in the preceding para- 

 graph can be almost entirely overcome even 

 with wheat taken from standing plants and 

 never allowed to dry out by the use of a lower 

 temperature than has been customary for 

 making the germination tests. Thus of 16 

 samples of fresJily harvested wheat an average 

 of 99 per cent, began to germinate in 5 days 

 at temperatures from 9° to 16° C. (48° to 

 61° F.), whereas in the same time an average 

 of only 86 per cent, germinated at 22° C. 

 (72° F.) which is about the temperature at 

 which germination tests of wheat are fre- 

 quently made. In the case of one lot 98 per 

 cent, were germinating by the end of 5 days 

 at 12° C. (54° F.) and only 16 per cent, at 

 22° C. (72° F.). About 15° 0. (59° F.) is 

 recommended for use in making germination 

 tests of all freshly harvested wheat. Of 

 course at this temperature the rate of growth 

 is slow after germination has begun. How- 

 ever, if one wishes to assure himself of the 

 normal character of the seedlings it is only 

 necessary to transfer the wheat grains as soon 

 as the coverings are split over the embryo to 

 some place where the temperature is about 

 20° C. (68° F.) and leave them at the higher 

 temperature for a day or two. 



A number of other methods have been dis- 



covered of overcoming this difficulty, at least 

 partly, but none is as satisfactory as the use 

 of a low germination temperature. Removing 

 the coats over the embryo by the use of con- 

 centration sulphuric acid, followed by neutral- 

 ization of the acid and washing, and a number 

 of mechanical treatments which consist es- 

 sentially of exposing the embryo to external 

 conditions have been markedly successful, but 

 are all tedious and some of them are attended 

 with great danger of subsequent decay of the 

 grain. 



Drying the wheat at about 40° C. (105° F.) 

 for a week had a somewhat beneficial effect 

 upon its germination, but this method of 

 treatment does not give wholly satisfactory 

 results and, together with the following ger- 

 mination test, consumes more time than can 

 be allowed, especially toward the end of the 

 fall sowing season. 



All of the methods which were beneficial 

 with winter wheat gave equally good results 

 with spring wheat and all except treatment 

 with sulphuric acid were used with more or 

 less success also in the germination of freshly 

 harvested barley and oats, with which the 

 same difficulty may be experienced as with 

 wheat. 



A full report of the investigation is to be 

 published shortly by the United States De- 

 partment of Agriculture. 



George T. Harrington 



Bureau of Plant Industry, 

 IT. S. Department of Agriculture 



SCIENCE 



A Weekly Journal devoted to the Advancement of 

 Science, publishing the official notices and pro- 

 ceedings of the American Association for 

 the Advancement of Science 



Published every Friday by 



THE SOENCE PRESS 



LANCASTER. PA. GARRISON, N. Y„ 



NEW YORK, N. Y. 



Enteied in the poal-affice at Lancaotct. Pa., at tecond clan matter 



