Meiotic restitution mechanisms and 2npollen formation in aSolanum tuberosumdihaploid and in dihaploid × wild species hybrids*

摘要

AbstractASolatium tuberosumdihaploid that proved to be a 2npollen producer, exhibited two types of meiotic abnormality involved in 2npollen formation: premature cytokinesis at prophase II and parallel/tripolar spindles in meiosis II. For this reason such a dihaploid was preferentially used as a seed parent in crosses with the diploid speciesS. tarijense, S. sanctae‐rosae, andS. phureja.Diploid interspecific hybrids were evaluated for male fertility, for 2npollen production and stability over three years and for meiotic nuclear restitution mechanisms. Pollen stainability ranged from 6 to 85 and 2npollen from 5 to 35 among hybrids. The meiotic mechanism generating 2n pollen was that of spindle abnormality in meiosis II and consequent dyad/triad formation. High correlation was found between fused/parallel spindles and dyad