Early postfertilization embryo sac development Triticum aestivum and xTriticosecale reciprocal crosses

Embryo sac development in reciprocal crosses of winter, hexaploid: wheat (Triticum aestivum L. cultivar ‘Liwilla’) and triticale (xTriticosecale Wittm. strain CHD 464) was examined during the first five days after pollination. Double fertilization was found in both crosses. Embryos developed regularly, slower however in the wheat ♀ x triticale ♂ cross. Aberrant, polyploid (up to 24n) endosperm nuclei were formed through disturbed mitotic cycles in both crosses. They occurred more frequently in the wheat ♀ x x triticale ♂ cross. Also, an early desynchronization of nuclear divisions and an uneven distribution of endosperm nuclei were found in the latter cross. They were accompanied with delayed or not complete cellularization of endosperm and its degradation in some regions. These abnormalities are the possible cause of the severe kernel sterility in the wheat ♀ x triticale ♂ cross. In contrast, the reciprocal cross produced shrivelled but mostly viable kernels.