Summary Cytological studies were made in hybrids between S. spontaneum L clone Iritty-2 (2nϭ64) and Erianthus arundinaceus (Retz.) Jesweit clone IK 76-99 (2nϭ60). The chromosome number of 19 hybrids ranged from 2nϭ78 to 86. Predominantly bivalent formation was observed at diakinesis and metaphase I stages in pollen mother cells of all the hybrids. At later meiotic stages abnormalities such as lagging chromosomes, multipolar spindles, abnormal planes of cytokinesis and micronuclei were present. In one hybrid CYM 04-391 with chromosome number 2nϭ80, the pollen mother cells had cytomixis and syncyte formation in the prophase stage. Certain syncytes had very high number of chromosomes in the form of bivalents at diakinesis and metaphase I, with nearly 80 to more than 600 bivalents. Fertile pollen was observed in few anthers of CYM 04-391 and the pollen size variation was high in it compared to that in the other similar hybrids.Key words Sugarcane, Saccharum spontaneum, Erianthus arundinaceus, Intergeneric hybrid, Meiotic abnormalities, Syncyte.Sugarcane (Saccharum spp. hybrid) is a major crop in the tropical and subtropical regions of the world grown mainly for sugar and ethanol. The commercial sugarcane varieties are complex derivatives of man made-interspecific hybrids involving the 'noble' cane Saccharum officinarum L. and the wild grass S. spontaneum L. in which other Saccharum species S. barberi Jesweit, S. sinense Roxb. and S. robustum Jesweit and Brandes ex Grassl. were also incorporated (Daniels and Roach, 1987). The chromosome number of the commercial sugarcane clones range between 2nϭ100 and 130, higher than that of the basic species S. officinarum (2nϭ80) and S. spontaneum (2nϭ64 or 80) involved in their origin (Sreenivasan et al. 1987). This is due to the phenomenon of 2nϩn transmission in crosses involving S. officinarum and S. spontaneum and also in the first back cross when S. officinarum is used as female parent. The 'Saccharum complex', proposed by Mukherjee (1957) includes the genera Saccharum, Erianthus Michx. sect. Ripidium Henrad, Sclerostachya (Hack.) A. Camus and Narenga Bor. which constitute a closely related interbreeding group. Later, Daniels et al. (1975) suggested to include Miscanthus also to the Saccharum complex. The origin of S. officinarum is still debated and the most plausible path of evolution was given by Daniels and Roach (1987) that it was originated in the East Indonesian/New Guinea area from S. spontaneum, Miscanthus sinensis and Erianthus arundinaceus (Retz.) Jesweit.S. spontaneum with wide eco-geographical distribution has many cytotypes with chromosome numbers ranging from 2nϭ40 to 128 (Panje and Babu, 1960;Sreenivasan et al. 1987). Janaki Ammal (1941) crossed S. spontaneum 'Glagha' (2nϭ112) with Erianthus ravennae (2nϭ20) and obtained hybrids having chromosome number 2nϭ66, resulting from nϩn transmission. The S. spontaneum 'SES 248' (2nϭ40)ϫE. ciliaris (2nϭ40) gave rise to hybrids with nϩn transmission