Patterns of meiosis in ABDR amphihaploids depend on the specific type of univalent chromosome division |
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| Authors: | Email author" target="_blank">O?G?SilkovaEmail author A?I?Shchapova V?K?Shumny |
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| Institution: | (1) Institute of Cytology and Genetics, Siberian Branch, Russian Academy of Sciences, Lavrentiev aven. 10, Novosibirsk, 630090, Russia |
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| Abstract: | Meiosis in wide F1 hybrids in the tribe Triticeae is complex and irregular. Despite extensive research, the meiotic pathways in such hybrids
remain largely unknown. In this study, the effect of the genotypes of disomic wheat–rye substitution lines on the regulation
of meiosis in ABDR amphihaploids was analysed by comparing microsporogenesis and seed set under self pollination in hybrids
of normal bread wheat (Triticum aestivum L.) and wheats with single chromosome substitutions 1R(1A), 1Rv(1A), 2R(2D)1, 2R(2D)2, 2R(2D)3, 5R(5D), 5R(5A), 6R(6A) with rye (Secale cereale L.). Three types of meiotic pathways were identified in the hybrids: reductional, equational, and equational+reductional.
During the reductional type division, chromosomes randomly moved toward the poles at Anaphase I (AI) and separated sister
chromatids at AII. Meiosis ended with tetrad formation, and the resulting plants were sterile ((2R(2D)1 × R, 2R(2D)2 × R). In the equational type division, the chromosomes aligned along the equator at Metaphase I and at AI separated into
chromatids that moved toward the poles. This meiotic pathway led to dyad formation and partial fertility (especially in hybrids
of 1Rv(1A) and 6R(6A)). In the equational+reductional pathway, some chromosomes divided in an equational manner while others
were segregated reductionally within the same microsporocyte and this led to formation of tetrads with groups of uncoiled
chromosomes. Comparison of the frequencies of each of the three meiotic pathways in different hybrid combinations suggests
differences in contributions of individual chromosomes to the control of the entire meiotic process. |
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