ABSTRACT
Many classical cytological studies have been performed in sugarcane (review by Sreenivasan et al. 1987). These studies delivered important information about the complexity of the genome of sugarcane and were also very useful to help unravel the taxonomy of the Saccharum genus. Chromosome numbers
were determined, uncovering highly polyploid and, frequently, aneuploid members in this genus. The vast majority of S. officinarum clones display 2n = 80 chromosomes. It has been suggested that the rare clones with higher chromosome numbers are hybrids (Bremer 1923; Sreenivasan et al. 1987). S. robustum largely encompasses clones with 2n = 60 or 80, but also includes many other forms that may have up to 200 chromosomes (Price 1965). Chromosome number in S. spontaneum varies from 40 to 128, with five major cytotypes: 2n = 64, 80, 96, 112, and 128 (Panje and Babu 1960). Pairing behavior was studied in these species that showed mainly bivalents, but various types of meiotic irregularities are also found (Bremer 1923; Price 1963; Burner 1991). The occurrence of 2n gamete transmission in hybrids between S. officinarum and S. spontaneum and their first backcross with S. officinarum was demonstrated (Bremer 1923, 1961).
