MEIOSIS IN TRIPLOID LOLIUM .1. SYNAPTONEMAL COMPLEX-FORMATION AND CHROMOSOME CONFIGURATIONS AT METAPHASE-I IN ANEUPLOID AUTOTRIPLOID L-MULTIFLORUM

A spreading technique for synaptonemal complexes (SCs) was applied to pollen mother cells of two aneuploid genotypes of autotriploid Lolium multiflorum (2n = 3x + 1 = 22). In the earliest nuclei analyzed the ax ial elements are in six groups of 3 and one group of 4. Most groups ha ve formed multivalents with from one to five pairing partner exchanges , but there are also groups that have formed bivalents and univalents. Some axial elements have formed triple associations, in one case for the length of the trivalent. Unsynapsed axial elements remain aligned with their homologous SCs into pachytene, but this alignment is abolis hed as these axes pair heterologously among themselves until the entir e axial element complement is synapsed. At metaphase I most chromosome s are associated as trivalents and quadrivalents.