Abstract
Meiotic studies were carried out in 47 diverse germplasm lines of Panicum maximum and various chromosomal associations during diakinesis, metaphase and anaphase were recorded. All the accessions showed a uniform chromosome number of 2n=32. High variability for chromosome associations was recorded within as well as between different accessions. Number of combinations of chromosomal associations per accession ranged from 2 to 11, with 1–3 quadrivalents being most abundant. Average association, with the exception of IG 01-104 in which a few hexavalents were observed, varied from 0.2 IV+15.33 II+1.13 I (IG 97-07) to 2.13 IV+11.73 II (IG 97-14). Pooled data revealed 85.1% chromosomes to be associated as bivalents followed by 14.5, 0.25, 0.05 and 0.01% as quadrivalents, univalents, hexavalents and trivalents respectively. Average chromosomal association in germplasm was 0.002 VI+1.16 IV+0.01 III+13.62 II+0.08 I. Basic chromosome number of 8 is proposed for the germplasm lines based on meiotic configurations from these accessions. Previous views on basic chromosome number and auto-allopolyploid origin of P. maximum is discussed.
