Cytogenetic study of an interspecific hybrid Helianthus praecox x H. annuus, its parental forms and two backcrosses

Meiosis of wild species (H. praecox) and cultivated sunflower (H. annuus), their F₁ interspecific hybrid as well as two backcross generations has been studied. A low level of chromosomal abnormalities in the parents was detected. Interspecific hybridization between the wild and cultivated samples has led to a considerable (50 %) increase of meiosis abnormalities in sunflower pollen mother cells. Backcrossing of hybrids by cultivated sunflower decreased the chromosomal abnormalities level to 12,8 % in BC₁ and 9,6 % in BC₂.Cytological stability of plants restored in BC₂ only.

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