Cytogenetical studies of triple hybrid from F1 Triticum turgidum×Secale cereale and Triitcum vulgare
II. A. Maturation division of pollen mother cells in F1 plants
1951 Volume 26 Issue 3-4 Pages 105-118
Details
1951 Volume 26 Issue 3-4 Pages 105-118
A cytological investigation on the Triticum-Secale triple F1 hybrids (20 individuals), raised from (T. turgidum×S. cereale)×T. vulgare, was carried out in maturation division of P.M.C.-s.
The number of somatic chromosomes has shown to vary from 39 to 42 according to the individuals.
The triple F1 hybrids, having 39-42 chromosomes, were raised from T. turgidum× S. cereale F1, the chromosomes of which being n=21, with T. vulgare.
21 chromosomes in the 39-42 ones mentioned above seem to have come from T. vulgare, and the remaining 18-21 chromosomes from F1 plants of primary hybrid, T. turgidum×S. cereale, respectively.
The number of bivalents in one P.M.C. at metaphase of first maturation division, has shown to vary from 10 to 17 in the individuals with 2n=39-42 chromosomes. Some gemini were seemed to be derived from allo-syndesis between the chromosomes of AB genoms of T. turgidum and T. vulgare, and one of the others, at least, to be resulted from auto-syndesis in R-genom of S. cereale, and the other ones to be from allo-syndesis between chromosomes of R-genom of S. cereale and D-genom of T. vulgare.
Some of these gemini were observed as univalents early in maturation division.
The number of univalents varied from 8 to 21 (Table 1, 2, 3 and 4). Trivalents and tetravalents were observed, and the number of them in a P.M.C. was only one in both cases.
The constitution of genoms according to the results from the present investigation on the maturation division in P.M.C.-s of these 20 individuals of triple hybrids, is as shown in the following table:
In maturation division the irregularity was observed generally at first and second divisions respectively, and consequently the cases, in which the tetrad consists of 2-9 cells instead of 4 cells, were sometimes observed. In many cases, in the cells consisting tetrad, those having some nuclei were found resulting from irregular divisions.
The number of chromosomes at metaphase of second division of P.M.C.-s was counted as 22-24 in A-group, as 18-27 in C-group and as 22-23 in D-group respectively.
At first metaphase of maturation division of Tri-F1-17, which ought have 2n=42 chromosomes in general, was observed a chromosome combination of 13II+30I=56. This case seems to be due to the duplication of chromosomes of both D-genom of T. vulgare and R-genom of S. cereale, i. e. 28 (14II=13II+2I)+14I(2D)+14I(2R)=56.
