Morphological variation in relation to chromosomal variation in Saccharum bengalense Retz. complex.

Abstract

Comparative morphological study of plant parts and floral parts in different chromosomal races of Saccharum bengalense Retz. complex is presented. Although variation between the cytotypes is basically of quantitative nature yet some of the characters help in distinguishing diploid (2n=20), tetraploid (2n=40) and hexaploid (2n=60) cytotypes in the field. A key has been suggested for this purpose. Hairyness of lower glume of sessile spikelet helps in distinquishing diploid from diploid with one to five accessory chromosomes, it being smooth in the latter. Stomatal size did not prove a reliable character to distinguish the diploids and the polyploids. Pollen size increased with the increase in ploidy level. Seed germination percentage was low in the polyploids compared to in the diploid. An interesting observation was that the gigas effect of ploidy existed upto tetraploid level only and in the hexaploid the effect is reversed. Karyotype was studied in different cytotypes and it was of symmetrical type.