CYTOLOGICAL RELATIONSHIPS OF SELECTED SPECIES OF PANICUM-L

The cytological investigation of 12 taxa of Panicum L. revealed that t he vast majority of them have the basic number x = 9 at different ploi dy levels. The basic number x = 8 was recorded only in the tetraploid species P. maximum with 2n = 32. The diploid number 2n = 18 was encoun tered in P. capillare, P. laevifolium, P. antidotale and P. coloratum (2) with 3B-chromosomes recorded in the latter species. The tetraploid chromosome number 2n = 36 was found to exist in P. miliaceum, P. mili are, P. coloratum (1) and P. virgatum. The hexaploid number 2n = 54 wa s recorded in P. bulbosum, P. dichotomiflorum and P. esculentum. The k aryotypes of all accessions were mostly symmetrical and mainly compris ed of meta-and submetacentric chromosomes with little variation in len gth among them within each karyotype. Investigation of chromosome asso ciation during metaphase I of meiosis revealed that the frequency of b ivalents/cell was the highest among all investigated diploid, tetraplo id and hexaploid accessions. Univalents were also frequently encounter ed in various accessions. These results may indicate that segmental al loploidy has been the major process by which polyploid species have or iginated.