ZUR GENETIK DES WEIZENS 89 
able to show true polymery, that in such species n chromosomes may 
carry the same or almost the same genes. If moreover the chromoso- 
mes occasionally change their position by the fusion so that f. 1. chro- 
mosome Nr. 1 © is joined with Nr. 2 ¢ and vice versa, the zygote would 
be double heterozygous in the genes in which the said chromosomes 
differed and complex mutations might be the result. 
18. As an other and independent assumption it might be imagined 
that the Normal type was not homozygotic but a complex heterozy- 
gote, which, with an almost complete heterogamy, bred nearly true to 
type. If the yielding ability, the great vigor and self-fertility of the 
varieties of cultivated wheat partly sprang from heterosis in a hetero- 
zygote of this kind, it would explain the fact, that the Speltoid hetero- 
zygote in which heterogamy would then be considered as partly bro- 
ken down by the mutation, not only shows a segregation of different 
types, but also a great variation in the heterogamous phenomena, fer- 
tility, vigor, etc. in the offspring. 
ZITIERTE LITERATUR. 
1. Coss, Friepa. 1921. A case of Mendelian inheritance by heterogametism 
and mutation in Oenothera pratincola. Genetics, Vol. 6, p. 1-42. 
2. East, E. M. and Jones, D. F. 1919. Inbreeding and outbreeding. London 
& Philadelphia. 
3. HERIBERT-NILSSON, Nits. 1920. Ein Übergang aus dem isogamen in den 
heterogamen Zustand in einer Sippe der Oenothera Lamarckiana. Here- 
; ditas, Bd I, S. 213—220. 
4. Kinara, H. 1919. Über zytologische Studien bei einigen Getreidearten. 
Bot. Mag. Tokyo, S. 17—38. 
5. MORGAN, T. H., STURTEVANT, A., MULLER, H. J.' Bridges, C. B. 1915. The 
Mechanism of Mendelian Heredity. New York. 
6. . NıLsson-EHLE, H. 1917. Untersuchungen über Speltoidmutationen beim 
Weizen. Botaniska Notiser, S. 305—329. 
7. — 1920. Multiple Allelomorphe und Komplexmutationen beim Weizen. (Un- 
tersuchungen über Speltoidmutationen beim Weizen II). Hereditas, Bd I, 
S. 277—311. 
8. — 1921. Uber mutmassliche partielle Heterogamie bei den Speltoidmutatio- 
nen des Weizens. (Untersuchungen iiber Speltoidmutationen beim Weizen 
III). Hereditas, Bd II, S. 25—76. 
9. SAKAMURA, T. 1918. Kurze Mitteilung über die Chromosomen und die 
Verwandtschaftsverhältnisse der Triticum-Arten. Bot. Mag. Tokyo, 32. 
10. STURTEVANT, A. H. 1920— 1921. Genetic studies on Drosophila simulans I—III. 
Genetics, Vol. 5 and 6. 
