March 8, 1918] 



SCIENCE 



247 



These studies are all based on the ear-to-row 

 test. Dent corn only was used in these tests. 

 They are not conclusive, but indicate the lines 

 of attack, and this statement is presented at 

 this time to call attention to the fundamental 

 relation of these investigations to seed selec- 

 tion and the germination test. Approximately 

 a hundred and fifty readings have been made 

 on the mother-ear, seed, seedlings, and field 

 performance of each of the ears. No ears are 

 referred to herein which did not have a hun- 

 dred per cent, germination record. The 

 germination records are based on twenty 

 kernels from each ear. The report of this 

 year's work is corroborated by the results of the 

 two previous years. 



Some of the most important results of the 

 experiments are : 



(a) That barren stalks and stalks bearing 

 only nubbins seem to be correlated with cer- 

 tain pathologic conditions in the plants. 

 There is also a correlation between certain 

 types of seedlings grown on a neutral-base 

 germinator and the number of barren stalks 

 that grow from the seed planted from the 

 same ears. 



(6) That in fifteen rows of corn grown this 

 season from ears which present this pathologic 

 condition in the seedlings, there were 15.2 per 

 cent, of the plants barren, and 6.2 per cent, of 

 the stalks bore nubbins only. In these rows 

 15.2 per cent, of the stalks were down by the 

 end of the growing season. In fifteen rows of 

 com grown from ears not having seedlings 

 which showed this pathologic condition, 6.3 

 per cent, of the stalks were barren, and 3.4 per 

 cent, bore nubbins only. In these rows 3.1 per 

 cent, of the stalks were down at the end of the 

 growing season. 



The computed diflference in yield between 

 these two series of rows was 22.6 bushels per 

 acre. The rows were distributed throughout 

 the tost plot, the high-yielding and diseased 

 rows alternating. 



(c) That this pathologic seedling type is 

 developed both on the neutral-base germi- 

 nator and in sterile agar flask cultures. 



(d) That surface sterilized seeds harbor 

 bacteria and species of Fusarium. The bac- 



teria cause a rotting of the seedling root tips 

 in the sterile flask cultures. This rotting of 

 the roots of the seedlings is the germination 

 characteristic of the ears of corn which de- 

 velop the greatest numbers of barren and down 

 stalks in the field. 



(e) By controlling fertilization by hand 

 pollinating ears of apparently disease free 

 plants with pollen from similar plants, the 

 amount of barrenness in the rows from these 

 ears was reduced to less than 1.5. per cent., 

 and with but 1.2 per cent, down-stalks at the 

 end of the growing season. 



(/) All kernels from the same infested ear 

 do not harbor pathogenic organisms within 

 them. Neither is the rate of seedling develop- 

 ment usually referred to as " vitality," a cri- 

 terion for assuming freedom from infestation 

 of the seed by bacteria and species of Fusar- 

 ium. The rate of seedling development on 

 the germinator is not indicative of the yield 

 possibilities of that seed ear. 



G. N. HOFFER, 



Purdue UNrvERsiTT, LaFatette, Ind. 



J. R. HOLBERT, 



Fdnk Seed Co., Bloominqton, III. 



THE AMERICAN ASSOCIATION FOR 



THE ADVANCEMENT OF 



SCIENCE 



SECTION F (ZOOLOGY) 



The Convocation Week meetings of Section F 

 (Zoology) of the American Association for the 

 Advancement of Science were held in conjunction 

 with those of the American Society of Naturalists 

 at Pittsburgh, Pa., December 31, 1917, and Jan- 

 uary first, 1918. The meetings of Monday, De- 

 cember 31, were in charge of the officers of Sec- 

 tion F and were presided over by Professor Her- 

 bert Osborn, professor of zoology in the Ohio 

 State University and vice-president of Section F. 

 In the absence of the secretary of the Section, 

 Professor W. M. Smallwood, of Syracuse Univer- 

 sity, acted as temporary secretary. 



At the Imsinoss meeting of the Section, Pro- 

 fessor L. B. Walton, of Kenyon College, was re- 

 elected member of the council; Professor V. E. 

 Shelford, of the University of Illinois, was chosen 

 member of the sectional committee for five years; 

 Professor C. H. Eigenmann, of Indiana Univer- 

 sity, was elected member of the general committee. 



