696 EXPERIMENT STATION RECORD. 



cliaracters are previously separated complete fixation may be seemed in two 

 generations. When the new character is a mosaic a longer time is recjuired, 

 as gametic contamination which is non-Mendelian in character is involved. 



Rejuvenation by Hybridization was the subject of an address by Q. I. Simp- 

 son. The vigor or energy of offspring, according to the speaker, is affected by 

 four factors — hybridization, crossing, change of nutrition, and change of climato. 

 'These factors were explained and illustrated in connection with a discussion 

 of the author's theory of "cell polarity," which has to do with the origin and 

 function of centrosomes. 



G. M. Rommel discussed The Inheritance of the Size of Litter in Poland China 

 Sows. Brief reference w^as made to the results of studies reported in Circular 

 ■Q5 of the Bureau of Animal Industry (E. S. R., 18, p. 267). More recent studies 

 (Of the inheritance of the size of litters from mother to daughter were reported. 

 The later results showed that the size of the litter increases with the age of the 

 sows from 1 to 5 years. The results also showed a tendency toward the trans- 

 mission of the size of litter, this being most marked in the case of the youngest 

 daughters. 



E. C Schroeder, in discussing Animal Breeding and Disease, stated tluit 

 ■disease is a disqualifying condition in any animal from which the highest type 

 of progeny is expected. This was illustrated by reference to specific diseases. 

 Means of eradicating certain diseases, especially tuberculosis, were discussed. 

 Special attention was called to the spreading of disease by the growing custom 

 of stabling animals by classes in exhibitions instead of by owners. Among other 

 topics discussed was the inheritance of susceptibility to disease. Tests carried 

 on for ten years have shown that the susceptibility of hogs to hog cholera varies 

 from an extremely high grade to absolute immunity. Great variation was also 

 observed in the susceptibility of cattle to Texas fever and other diseases. Efforts 

 are now being made to obtain a breed of hogs immune to cholera by breeding 

 from naturally immune stock. Mention was also made of other lines of work 

 similar in character in which the Bui'eau is engaged. 



Corn Breeding and Registration was discussed by C. G. Williams, who con- 

 sidered the ear-row test the proper basis for this work. Ears for this test 

 should be selected upon the growing plant in order that environment may be 

 noted and the first step taken in sifting the inheritably good from the acci- 

 dentally good. The ear-row test may be employed without regard to other 

 cornfields. In order to overcome differences in environment this test should 

 be made in duplicate, with uniform check rows at regular intervals. The 

 value of this duplication was illustrated by the work of Ohio breeders. 



One-third to one-half of the seed grain of each ear should be saved for use 

 in tlie breeding plats when the test has demonstrated which the high-yielding 

 ears are. The remnants of the high-yielding ears are crossed the year follow- 

 ing the test, one being used as sire upon several detasseled dams. A plan for 

 f'ontinuous corn-breeding work was presented in which inbreeding was thought 

 to be provided against. Rules were given for the registration of pedigreed 

 and merged strains of corn as adopted by the Ohio Plant Breeders' Associ- 

 :ation. 



The breeding of tobacco with particular reference to the work of this Depart- 

 ment was discussed by A. D. Shamel. 



A review of Tobacco Breeding in Ohio was presented by A. D. Selby. Th.^ 

 State has four tobacco districts in which characteristic and distinct varieties 

 are grown. Efforts at crossing the Connecticut seed leaf with the Cuban seed- 

 leaf tobacco in the cigar-filler district have resulted in the production of 35 or 

 more hybrids which are being tested. New wrapper tobacco hybrids have 

 also been produced and are being subjected to tests. 



