Cytogenetical studies on <i>Triticum dicoccum×Secale Vavilovii</i> F<sub>1</sub> hybrid

Abstract

1. In this investigation, the F1 plant raised between Triticum dicoccum var. atratum and Secale Vavilovii was studied cytogenetically.2. 2974 spikelets on 128 spikes of T. dicoccum var. atratum were pollinated with the pollen of S. Vavilovii, and 25 kernels were obtained. Each of these kernels was sown in separate pots, and from them only one F1 hybrid was raised. The percentage of the F1 individual to the number of all the pollinated spikelets was 0.0336 percent. In this investigation, 8 combinations of hybridization between Emmer wheat (8 species) and S. Vavilovii were tried, but in 7 combinations among them no F1 plant was obtained (Table 1).3. Almost all the external characters of the F1 plant, except one or two, resembled more closely to T. dicoccum var. atratum than being intermediate between the parents. Colour of spike was purplish black, and almost looks like that of T. dicoccum var. atratum. The spikelet of F1 was not so brittle at the ripening stage as in the F1 T. dicoccum var. atratum× S. cereale.4. The number of chromosomes was counted to be 21 as 2n at the heterotypic division in PMC's of the F1 and it corresponds to the sum of the reduced chromosome numbers of the parents. At heterotypic metaphase in PMC's of the F1 plant, 0_??_4 bivalents and 13_??_21 univalents were observed (Table 3). The frequency of the bivalents in PMC's is shown in Table 3, and the case of zero appears to be the mode. Stick-shaped bivalents formed by 2 elements of equal size conjugated end to end were generally observed, and as a rare case, a ring-shaped bivalent in which two equal sized elements closely conjugated was also observed (Table 3). Those bivalents up to 4 may probably be made by autosyndesis between the chromosomes of AB genomes of T. dicoccum var. atratum. used as the mother plant. No tri-and tetravalent were observed.5. At heterotypic anatelophase of PMC's the chromosomes were distributed to the opposite poles 0:21_??_10:11, and the distribution 10:11 appeared to be the mode. (Table 4).6. At heterotypic metaphase of PMC's univalents were normally scattered in the spindle, but in some cases the formation of equatorial or semi-equatorial plate was observed, and consequently non-conjugation and the formation of restitution nucleus were rarely observed. Almost all the anthers of F1 were not opened and the pollen grains showed almost sterile, but on rare occasions, some anthers were opened and a few kernels (21) were obtained in natural selfing.