Cytological evidences of SDR-FDR mixture in the formation of 2n eggs in a potato diploid clone.
Macrosporogenesis and microsporogenesis were investigated in a diploid S. tuberosum x S. chacoense potato hybrid, characterized by more than 50% 2n egg formation. Fifty-five percent of dyad formation of 2n macrospores is ascribed to two meiotic abnormalities: omission of the second meiotic division, occurring at a frequency of 38%, and irregular spindle axis orientation at metaphase I at a frequency of 16%: These abnormalities give origin to a mixture of 2n eggs, composed of mostly second division restitution (SDR) and a small portion of first division restitution (FDR). Microsporogenesis showed rare dyads of 2n microspores depending on parallel spindles observed in anaphase II.
Center of Vegetable Breeding, CNR, Portici, Italy.
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Conicella
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Barone
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Del Giudice
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Frusciante
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Monti