Cytology of Sexual and Apomictic Paspalum Species

Abstract

The cytology, reproductive behavior and fertility of seven different Paspalum species were studied to determine how they might be used in an interspecific hybridization program. Paspalum palustre Mez and P. bertonii Hack. were diploids with 2n=2x=20 chromosomes. Paspalum dedeccae Quarín; P. denticulatum Trin., and one P. distichum L. accession were tetraploids with 2n=4x=40 chromosomes. Another P. distichum accession, P. inaequivalve Raddi, and P. ramboi Barreto were hexaploids with 60 chromosomes. Meiosis was regular with primarily bivalent pairing in P. palustre, P. bertonii, tetraploid P. distichum, P. inaequivalve and P. ramboi. Paspalum dedeccae, two P. denticulatum accessions, and hexaploid P. distichum were meiotically irregular with univalent, bivalent and multivalent (primarily quadrivalent) associations at metaphase I. Megasporogenesis and embryo sac development in P. palustre, P. bertonii, and P. inaequivalve indicated sexual reproduction. Paspalum palustre and P. bertonii were self-incompatible and did not produce self-pollinated seed but P. inaequivalve was self-compatible. Paspalum dedeccae, P. denticulatum, P. distichum, and P. ramboi all reproduced by aposporous apomixis. © 1991, Japan Mendel Society, International Society of Cytology. All rights reserved.