254 Vererbung, Variation, Mutation. 



zustande kämen. Gates lehnt diese Auffassung ab, weil sie die cytologischen 

 Tatsachen nicht berücksichtige. Wenn auch manche Merkmale von Oenothera 

 mendeln, so sei doch das plötzliche Entstehen der Riesenrasse und ihre darauf- 

 folgende Variabilität auf die Vergrößerung der Chromosomenzahl und teilweisen 

 nachträglichen Verlust von Chromosomen zurückzuführen. 



Schüepp (München). 



803) Funk, E. D., Ten Years of Corn Breeding. In: Amer. Breeders Mag., 

 Vol. m, Nr. 4, S. 295—302, 1912. 



After a selection of ten years from some of the highest yielding strains of 

 Funk's Gold Standard Leaming and Funk's Yellow Dent Maize, both varieties 

 show a tendency toward the same type and neither of them conform to the type 

 for a perfect ear. In general the increase has been about 15 busheis to the acre. 

 Experiments showed that the smooth type of corn made the highest yield. 



Pearl (Orono). 



804) Emerson, E. A. and East, E. M., The Inheritance of Quantitative 

 Characters in Maize. In: Bull. Agr. Exp. Sta. Nebraska, Research BulL 

 No. 2, S. 1—118, 1913. 



The authors report and discuss the results of an extensive investigation on 

 the inheritance of quantitative characters in maize. In general, it may be said 

 that the results secured in the experiments were what might well be expected 

 if quantitative differences were due to numerous factors inherited in a strictly 

 Mendelian manner. 



The inheritance of number of rows per ear has been studied in eight 

 different crosses. The parental varieties used were 8-rowed, 12-rowed, 16-rowed 

 and 20-rowed types. In nearly every case F^ was intermediate between the 

 parents. In most cases the Fg generations had a wider ränge of Variation than 

 Fj and included both parent types. When F3 f amilies were grown, the parent 

 types were recovered in every case and intermediate types were also seen. 



Inheritance of length of ear was studied, the ear length of one parent 

 being approximately two and one-half times that of the other parent. Tom 

 Thumb crossed with Black Mexican showed the F^ ear length intermediate between 

 the parental ear lengths. Missouri dent with California pop showed the F^ ears 

 to be practically as long as those of the longeared parent. This was doubtless 

 due to heterozygosis, for the means of the Fg families were distinctly intermediate 

 between parental means. In every case Fg fraternities were more variable than 

 the F^ lots, in most cases completely bridging the gap between the parents. 

 The short-eared parent type has not as yet been recovered in any F3 lot and in 

 only a few families has the ear length been equal to that of the long-eared 

 families. 



Inheritance of diameter of ears in two crosses showed the ears of F^ to 

 be intermediate between those of the parents but somewhat nearer the large- 

 eared than the small-eared variety. The Fg ranges of Variation little more than 

 filled the gap between the parent races. In F3 the parent types were not reco- 

 vered but several of the lots were very distinct. 



Weight of seeds was determined for the cross Tom Thumb with Black 

 Mexican. The Black Mexican seeds were probably a little too large owing to 

 previous mixture of strains. Allowing for this, the F^ seed weight was only a 

 little below the mid-i)arental weight and the ranges of Variation in the Fg frater- 

 nities well-overlapped the ranges of the parents. Distinct types of seed weight 

 were isolated in F3 but neither parent type was recovered. 



