| Unfortunately, in this experiment it was impossible to determine whether
the Do wheat line suppression of homoeologous pairing is equivalent to that
in other wheats. In general, ours involved hybrids show more chromosomes
paired per PMC than those described in the literature. This may be due either
to the difference in pairing control system or to the difference in external
factors. Temperature is known to affect homoeologous pairing (KATO and YAMAGATA
1979). The between-year variation in pairing in BC1 may reflect
the influence of environmental factors. Moreover, the formation of trivalents
(mostly wheat-wheat-rye type in this F1) was rarely reported
in ABR F1. The F1 (T. persicum x T. dicoccoides) x S. cereale F1 hybrid showed high pairing level (17,28I+1,66II+0,13III+0,003IV, LUKASZEWSKI, 1975). From indirect evidence based on the range of variation of the chromosome number in functional female gametes of F1 it may be expected that all other lines selected by Lapinski (LAPINSKI et al. 1979) from this cross show pairing level simillair to Xu, the Do line being exceptional among all the selected progeny (LUKASZEWSKI, APOLINARSKA, LAPINSKI, SODKIEWICZ 1979). NAKAJIMA (1956) found T. persicum to form more bivalents in F1 hybrids with S. cereale than any other tetraploid wheat he studied. The described character of weaker suppression of homoeologous pairing might have been inherited from this species. DALAL and SADANAGA (1965) have shown T. persicum to carry reciprocal translocation involving chromosomes 2B and 3A. According to DRISCOLL (1972), 3A chromosome of Chinese Spring carries homoeologous pairing suppressor. However, presented results do not allow for any statement on mechanisms involved and this problem needs further studies. Literature Cited BENNETT, M.D., J.P. GUSTAFSON, J.B. SMITH. 1977. Chromosome (Berl.) 61: 149-176 DALAL K.C., K. SADANAGA. 1965. Can. J. Genet. Cytol. 7: 88-96 DRISCOLL C.J. 1972. Can. J. Genet. Cytol. 14: 39-42 KATO, T., H. YAMAGATA. 1979. Jap. J. Genet. 54: 21-26 LAPINSKI B., A.J. LUKASZEWSKI, W. SODKIEWICZ, B. APOLINARSKA. 1979. Proc. EUCARPIA Meeting on Triticale (in press). LUKASZEWSKI A.J. 1975. In: Prace Grupy Problemowej Triticale w 1974, IHAR 80-85 LUKASZEWSKI A.J., B. APOLINARSKA, B. LAPINSKI, W. SODKIEWICZ. 1979. Proc. EUCARPIA Meeting on Triticale (in press). NAXAJIMA G. 1956. WIS 3: 25-26 OKAMOTO M. 1957. WIS 5: 6 RILEY R., V. CHAPMAN. 1958. Nature 182: 713-715 RILEY R. 1968. Proc. 3rd Int. Wheat Genet. Symp.: 185-195. SEARS E.R. 1975. Genetics 80, 3: 74 |
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