Cytogenetical studies on the i, ntergeneric F1 hybrids between Triticum compactum and three species of Secale.

1. In the present investig, ation, cytogenetical researches of the F1 plants rai, sed fyom Triticum compdctum. with 3 species of Secale (Vavilovii, africaleulev and montanum) were darried out.2. The percentage of the F1 plants to the number of th, e pollinated flowers in the hybrid between T. compactum and Vavilovii showed the highest and that of the hydrid with montaleum the lowest (Table 1). 3. The external characters of F1 raised frbm the 3 combinations, resembld those of the parents, but more closely the mother plant T. compactum than the, interrflediate of both parents. 4. The seed fertility of the hybrid TeomSaF1 was superior to that of the TcomSVF1 The hybrid TcomSmF1 showed complete sterility (Table 3). 5. The number of somatic chromosomes in root Table 13, Frequency between T. tip cells of the 3 F1 hybrids was 28 which corresponds exactly to the sum of the gametic number of chromosomes of the parents. 6. Though mother plant was common, the F1, hybrids of the 3 combinatiQns showed difference in the number of bivalents owing to the different pollen parents used. 7. In the 3 F1 hybrids, the nurhbe, r o, f bivalents at heterotypic metaphase of PMC's is as given in Table 13 (for details, see Table 4, 6 and 10). 8. In the hybrids of TcomSVF1 and TcomSaF1 the formation of equatorial plate in heterotypic m. etaphase of PMC's was observed occasionally, in addition to the normal F1 type division commonly observed for the wheat-rye Fl hybrid., The frequency of occurrence of the formation of equatotial plate is as giyen in Table 5 and 7.