Akira MOCHIZUKI
Laboratory of Genetics, Hyogo Agricultural College, Sasayama, Japan.
Plants in the first generation in Kyoto and Sasayama, Japan, from the original materials, which were collected by the BMUK2) from four different locations in central Turkey in 1959, have been used for the present studies.
In order to find B-chromosomes, young leaf meristems of a total of 573 plants were cytologically examined. B-chromosomes were found in all the populations varying in the number from one to five in invidual plants. Plants having two B-chromosomes were most frequent. The data are shown in the following table:
The B-chromosomes found in these populations seem to be identical with those that were previously reported (Mochizuki, 1957). They are euchromatic, are smaller than the smallest ordinary chromosomes of the complement, have median centromere and are unstable in the root tissue.
As an exceptional case, a deficient type of B-chromosome was found together with standard B's in a plant collected in a place near Ankara. This new type of B-chromosome is telocentric and forms a heteromorphic pair with a standard B.