Summary
In order to elucidate the mechanism of low fertility of Brassicoraphanus, i.e., amphidiploids between Brassica japonica Sieb. and Raphanus sativus L., the chromosome number of 253 plants was studied during the 3rd–9th generations for their seed fertility. Meiotic irregularity showed no connection with degree of sterility. Brassicoraphanus consisted of euploids (2n=38), hyperploids (2n=39–43) and hypoploids (2n=34–37) with white or yellow flowers. The number of plants was highest in euploids and became lower as the chromosome number diverged from the euploid number. Further, seed fertility was highest and the range of its variation widest in euploids. The seed fertility of aneuploids became lower and its variation narrower in proportion to the number of chromosomes additional to or missing from the euploid number. Yellow-flowered plants were superior in seed fertility to white-flowered plants. Seed fertility of plants is primarily affected by their chromosome numbers and secondarily modified by genic effects. As a whole, seed fertility of Brassicoraphanus increased gradually and its variation widened with the advance of generations. This was explained mainly by the increase of balanced combinations of genes.
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References
Dolstra, O., 1982. Synthesis and fertility of Brassicoraphanus and ways of transferring Raphanus characters to Brassica. Agr. Res. Rep. 917 Pudoc (Wageningen) 1–90.
Ellerström, S. & L.Zagorcheva, 1977. Sterility and apomictic embryo-sac formation in Raphanobrassica. Hereditas 87: 107–120.
Fukushima, E. & S.Iwasa, 1964. A spontaneous haploid plant in a certain Brassico-Raphanus hybrid strain. Proc. Jap. Acad. 40: 232–235.
Howard, H.W., 1938. The fertility of amphidiploids from the cross Raphanus sativus x Brassica oleracea. J. Genet. 56: 239–273.
Iwasa, S. & S.Ellerström, 1981. Meiosis disturbances, aneuploidy and seed fertility in Raphanobrassica. Hereditas 95: 1–9.
Karpechenko, G.D., 1927. The production of polyploid gametes in hybrids. Hereditas 9: 349–368.
Kato, M. & S.Tokumasu, 1976. The mechanism of increased seed fertility accompanied with the change of flower colour in Brassicoraphanus. Euphytica 25: 761–767.
Kato, M. & S.Tokumasu, 1983. The stabilization of chromosome numbers and the maintenance of euploidy in Brassicoraphanus. Euphytica 32: 415–423.
Kondo, N., 1942. A new Raphanobrassica from the cross, 4x-Raphanus sativus L. x 4x-Brassica oleracea L. Jap. J. Genet. 18: 126–130.
McNaughton, I.H., 1973. Synthesis and sterility of Raphanobrassica. Euphytica 22: 70–88.
Richharia, R.H., 1937. Cytological investigation of Raphanus sativus, Brassica oleracea, and their F1 and F2 hybrids. J. Genet. 34: 19–44.
Tokumasu, S., 1970. Intergeneric hybrids between Brassica japonica and Raphanus sativus. Mem. Col. Agr., Ehime Univ. 14: 285–302.
Tokumasu, S., 1976. The increase of seed fertility of Brassicoraphanus through cytological irregularity. Euphytica 25: 463–470.
Tokumasu, S. & M.Kato, 1980. Cytology, fertility and flower colour in hybrids between Brassica japonica and Raphanus sativus, and the synthesis of new Brassicoraphanus. Jap. J. Breed. 30: 11–19.
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Tokumasu, S., Kato, M. Chromosomal and genic structure of Brassicoraphanus related to seed fertility and the presentation of an instance of improvement of its fertility. Euphytica 39, 145–151 (1988). https://doi.org/10.1007/BF00039867
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DOI: https://doi.org/10.1007/BF00039867