Intraspecific inflorescence and palynological variations in the morphotypes of Amorphophallus paeoniifolius

The genus Amorphophallus Blume ex Decne. is a vast and widespread group of aroids belonging to Araceae which is taxonomically and botanically distinct due to the occasional emergence of inflorescences and their relatively short active period of existence. Seven morphotypes of Amorphophallus paeoniifolius which included two cultivated forms—the cultivated elephant foot yam ( A. paeoniifolius var. campanulatus) and another cultivar ‘Karunaikizhangu’, unique due to the presence of small corm and numerous elongate cormels, grown only in Tamil Nadu, in the southmost part of India, also known as A. paeoniifolius var. campanulatus , and five wild types belonging to Amorphophallus paeoniifolius var. paeoniifolius were studied. Elephant foot yam is an important tuber crop and the wild congenerics of the cultivated form possess powerful therapeutic action against piles and gastro-intestinal disorders. Variation in the surface pattern of petiole and spathe is the main difference found within the species. The shape of appendix, the colour and pattern of spathe, scale leaves (bract) subtending the spathe, the male zone, female zone, the pollen morphology as assessed by SEM and pollen fertility showed distinct variation within the species revealing six distinct morphotypes. The inflorescence/floral markers and vegetative morphological descriptors, pollen morphology, karyomorphological analysis which indicated structural variation in chromosomes resulting in varying number of median, sub-median and nearly sub-median chromosomes in the morphotypes and ISSR markers indicated clear distinction between the morphotypes, which lead to the conclusion that the above two cultivated types and accession P19 of A. paeoniifolius var. paeoniifolius, which had heteromorphic pollen can be considered as different botanical varieties.