TATIANA BOFF and MARIA TERESA SCHIFINO-WITTMANN

Departamento de Plantas Forrageiras e Agrometeorologia, Faculdade de Agronomia, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil

Abstract

Pollen fertility and meiotic behaviour were analysed in some taxa of the Central American nitrogen-fixing multipurpose tree genus Leucaena. Pollen fertility exceeded 90% in most of the 26 accessions of 13 species [L. confertiflora, L. diversifolia, L. involucrata, L. leucocephala, L. pallida, L. cuspidata, L. lanceolata, L. pulverulenta, L. retusa, L. salvadorensis, L. shannonii, L. trichandra, (L. × spontanea)]. Chromosome associations at diakinesis and metaphase I were analysed in 14 accessions of L. diversifolia, L. pallida, L. pulverulenta, L. retusa and L. trichandra and in the L. hybrid? accession. The diploid species L. pulverulenta, L. retusa and L. trichandra presented regular chromosome pairing, mostly in bivalents, but 1 or 2 quadrivalents were observed in some cells. In the tetraploid L. diversifolia and L. pallida, the most common chromosome associations were also bivalents but quadrivalents were found in up to 67% of the cells of L. pallida. The L. hybrid? accession presented several irregularities, such as univalents and multivalents and chromosome stickiness, reflected in low pollen fertility. Further analysis of more species and accessions and a detailed study of meiotic behaviour are underway.