抄録
1 The occurrence of twin plants and of the chromosome aberrations accompanied was exmined on the seeds of Norin No. 4, produced in the following localities: Okayama, Hiroshima, Shimane and Nara.
a) The chromosome aberration types detected in the twin plants were as follows: 42-21, 41-20, 42-63 and 42-84 (Table 2).
b) The frequency of twinning and of the occurrence of these chromosome aberrant halves were obviously greater in Okayama seeds than in the seeds from other localities (Table 1 & 2).
2 The seeds obtained from Okayama and Shimane were sown, in the fall of 1940, in Nagano, and the seeds produced in the following spring were examined.
a) The frequency of twinning and of the occurrence of the chromosome aberrant halves were again greater in Okayama-line than in Shimane-line (Table 3 & 4).
b) From these facts it may be concluded that the laocal difference of the frequency of twinning and of the occurrenec of the chromosome aberrant halves may be due to genetical differences which were induced by environmental dispafity in these localities,
