Chromosome Studies on the Pollen Nuclei of Some Cereals

Abstract

In the present paper the metaphasic chromosomes of primary nuclear division in pollen grains of Aegilops, Triticum, Secale and Hordeum were studied (Table 1).
For the fixing and staining of pollen grains, the same methods as employed in the writer's former work (1934) were adopted.
In Ae. speltoides and T. monococcum, all the chromosomes in a set show remarkable constrictions located at medium or submedium. One of 7 chromosomes is peculialy marked by the presence of a large appendage attached to the proximal end of its short arm beyond the broad achromatic zone as already mentioned in S. cereale by the writer (1934). So, it is easy to distinguish it from the other ones by this morphological speciality. Such chromosomes were observed in the other 9 forms studied.
Agronomic variety“Norin No. 7”of common wheat, which is the product of a cross between“Australian No. 13”and“Shirachabo, ”did not show any abnormality in the chromosome shape (Text-fig. 7), while one abnormally small chromosome (s) was observed in anotherr variety “Shirokomugi No. 1” (Text-fig. 8).