1. The meiosis of PMC's of 35 individuals of F
2 raised between two species of
Triticum and
Secale cereale is described.
2. The number of bivalents observed in one PMC is 11-23 at the heterotypic metaphase of
Triticum-Secale triple F
2 plants, and the frequency of those bivalents is shown in Table 1. And the mode of the number of bivalents was 14
II in the individuals having 2n=28-32 chromosomes, 15
II in those of 2n=33-37, 15
II-19
II in those of 2n=38-44 and 17
II-21
II in those of 2n=45-50. Generally, the number of bivalents increases as the number of chromosomes increases; showing that the number of homologous chromosomes will also increase when the number of chromosomes increases.
3. Trivalents or tetravalents, suggesting that the plants have 3 or 4 homologous chromosomes.
4.
Triticum-Secale triple hybrids employed in the present research are of the 2nd generation raised from the hybridization between two species of
Triticum and
Secale cereale each of which has quite different nature. Therefore, the meiosis in PMC's is very anomalous.
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