Abstract
Studies were made on the external morphology, meiotic divisions, pollen fertility and pollen size in three main Japanese varieties of Amorphophallus Konjac : Bittyu Zairai and Chinese (Shina). (1) These three varieties resemble mutually in external morphology except for some differences in size of the spot on leafstalk ; size, number and colour of leaflet ; etc. (2) At diakinesis and metaphase-1 of meiosis, partially asynaptic cells were observed in the three varieties, the proportions of these cells being approximately 15% in Chinese (Shina), 26% in Zairai and 40% in Bittyu, respectively. The cause of the partial asynapsis in these cases is unknown, but it might be due to the effect of the low temperature on the gene action. An early variety as Bittyu, in which meiosis takes place during late March and early April, would be more affected by the low temperature, while a late variety as Chinese (Shina) would be less affected. (3) The early variety Bittyu showed 25∼35 % pollen sterility and non-dehiscent anthers, probably resulting from the irregular meiosis. (4) Mainly on the basis of the chromosomal affinity shown in the F1 hybrid between Chinese (Shina) and Zairai, it can be stated that their genomic constitutions are identical (AA).
