256 Vererbung, Variation, Mutation. 



favorable en^dronment. These experiments were started in Iowa and removed to 

 Colorado before the seedlings began to fruit. Different environment caused a 

 change in the color of the fruit and stimulated early bearing, but did not de- 

 crease the size, quality or quantity of the fruit. 



An acclimatized sugar maize was obtained by crossing a small semi-dent 

 variety, which matured at an altitude approaching 8000 feet, with Cory. The 

 acclimatized parent doniinated all vegetal factors, the root System, the height of 

 the stalk, distance of the first ear from the ground, etc. This sugar corn was 

 bred back with the original base producing excellent results. 



The author also carried on experiments on the Rhode Island ßed breed of 

 poultry to test the principles of heredity and dominance. Barred Rock female 

 and Red male were crossed. Some of the F^ individuals of this cross were bred 

 with a Wyandotte-Minorca cross and a wide diversity obtained. Atavism is sta- 

 ted to have been the most striking feature of this experiment. The author found 

 that w^hen the potency of two or more correlative factors is nearly or quite 

 equal, dominance disappears resulting in a blend. Pearl (Orono). 



806) Belling, J., Third Generation of the Cross between Velvet and 

 Lyon Beans. In: Rept. of Fla. Agr. Exp. Sta., S. CXV— CXXVII, 1912. 



Seeds of more than a third of the seed bearing plants of the second gene- 

 ration of the Lyon-Velvet cross were sown among thickly planted sorghum in 

 Order that the strongest might be automatically selected. Out of 6093 seeds 

 only 740 surviving plants bore pods. On the whole there appeared to be a 

 selective elimination of plants with certain recessive characters. There is evi- 

 dence that the recessive character of black shoots and "smooth" pods (short or 

 soft velvet hairs) is accompanied by less vigorous growth. The differences of 

 pod-length in the different parents were (apart from obvious segregation) mostly 

 repeated in the third generation. The high breadth-length index of the seeds 

 of many plants is probably determined mechanically by the shortness of the pods. 



Pearl (Orono). 



807) White, 0. E., The bearing of teratological development in Nico- 

 tiana on theories of heredity. In: Amer. Natural., Bd. 47, S. 206 — 228, 

 1913. 



Describes the inheritance of a fasciated mutant of tobacco (Nicofiana taba- 

 ciini) which occurred in a Cuban tobacco field in 1907. Five generations of the 

 strain were grown (over 1000 plants), and all possessed the characters of the 

 original mutant. Though there was considerable Variation in the development of 

 the peculiarity, no reversions occurred. The fasciations were accompanied by 

 various abnormalities of the flowers. Crosses with other species were sterile 

 though the abnormality showed its effect on the F^. Crossed with the normal 

 variety the Fx was intermediate and the F^ split in the ratio 1 : 2 : 1. 



The chromosome number is determined as 48 (sporophytic), 24 (gameto- 

 phytic). In the abnormal races various irregularities in the reduction phenomena 

 are mentioned, but without any figures. Thus 51 Chromosoms were found in one 

 pollen mother cell, and 30 in another, and the heterotypic distribution was some- 

 times irregulär. It is concluded that in the fasciated race some abnormality is 

 at work producing aberrations of cell structure as well as of external characters. 

 A f ulier description, with figures, is desirable. Gates (London). 



808) Wellington, R., Studies of natural and artificial parthenogenesis 

 in the genus Nicotiana. In: Amer. Natural., Bd. 47, S. 279 — 306, 1913. 



