Vererbung, Variation, Mutation. 367 



Yererbuiig, Variation, Mutation. 



1165) Haecker, V., Untersuchungen über Elementareigenschaften. In: Verhandl. 

 deutsch, zool. Gesellsch., S. 317— .'319, 1912. 



H berichtet in einem kurzen Auszug über den Fortgang seiner r.)04 begonnenen 

 Kreuzungen zwischen der schwarzen und weißen Rasse des Axolotls {Aviblystoma mexicanum), 

 die bis zur vierten Generation gediehen sind. Ein ausführlicher Bericht i^t inzwischen 

 in der Zeitschr. f. indukt. Abstanimungsl. erschienen (vgl. Ref. Nr. 812). 



Schellack (Berlin). 



1166) Collins, G. N., Heredity of a Malze Variation. In: U. S. Dept. of 

 Agr. Bur. Plant Industry, Bull. 272, S. 1—23, 1913. 



This paper records the occurrence, and describes the results of the sub- 

 sequent experimental breeding of an albino mutant of a strain of yellow dent 

 malze {Zea mays). The author's concluslons are as follows: 



"It Las been assumed that alternative characters when brought together in 

 hybrlds will separate and reappear in pure form, unchanged by the temporary 

 Union. The endosperm characters of malze afford excellent materlal for the study 

 of this question and have played an Important part In establishing the theory of 

 complete segregatlon. The numerlcal regularlty wlth which many characters reap- 

 pear In the later generations of a hybrid is one of the chlef arguments for the 

 theory of segregatlon or alternative transmlsslon. The results here reported of 

 the Inherltance of an alblnistlc Variation seem to demonstrate that In this In- 

 stance, whlle the original characters reappear, they are not the same; In other 

 words, the segregatlon Is not complete. Prevlous experimenters In this field have 

 found the endosperm color somewhat refractory as an example of the segregatlon 

 theory, but by subdlvldlng the character Into factors It has been possible to bring 

 thelr results Into conformlty wlth the theory. The results here reported do not 

 lend themselves to such an explanatlon. The study Is based on the progeny of a 

 white ear that appeared in a carefully selected yellow varlety. The clrcumstances 

 under whlch the Variation appeared, as well as the behavlor of the progeny, 

 show that the occurrence of this white ear can not be ascrlbed to the accldental 

 admlxture of seed but must have arlsen as an abrupt mutatlve change of cha- 

 racters. In the original mutatlon the white color was almost completely dominant 

 over the yellow. In subsequent generations, however, the yellow reappeared as 

 a dominant character, though variable In Intenslty. The results accord numerl- 

 cally wlth the Meudellan expectatlon, but the recesslve white seeds Instead of 

 belng pure show mlnute traces of yellow. 



Imperfect segregatlon must be taken Into conslderatlon as an obstacle to 

 securlng comblnatlons of characters by hybrldlzlng. The occurrence of Mendellan 

 ratlos cannot be taken as concluslve evldence that subsequent selectlon will not 

 be necessary to establish the füll expression of characters." Pearl (Orono). 



1167) Gernert, W. B. (Illinois, University), A new subspecies of Zea mays L. In: 

 Amer. Nat., Bd. 46, S. 616— 02-2, Fig. 3, 1912. 



Describes a new type of ear which originated suddenly in an experimental field of 

 maize. The new type breeds true to the new character and has been called Zea ramosa 

 in accordance with the claesification of Sturtevant. This ear is conical in shape and is 

 irregularly branched, the branches bearing the kerneis. The tassel or male inflorescence 

 is branched in a similar way. Of the kerneis planted from the original ear only two out 

 of 50 gave the new character. These in the next generation both came true, showing 

 that the new character is recessive. Gates (London). 



1168) Rogers, C. A., Constltutlonal Vigor In Poultry. In: Cornell Univ. 

 Agr. Exp. Stat., Bull. 318, S. 573—614, 1912- 



