Abstract
The present population is pentaploid with seven as the basic number. The karyotype shows that all the chromosomes are median or submedian. However, four submedian chromosomes have their smaller arms, rather shorter than the smaller arms of the remaining submedian chromosomes. Two of these have an exaggerated centromere and have a secondary constriction located very near it. The karyotype can be relegated into two sets of 14 chromosomes each, and another set of 7 chromosomes.
At meiosis pentavalents to univalents are organized. Higher associations occur in a lower frequency, The maximum number of bivalents is 14, which are accompanied by 7 univalents.
At anaphase-I unequal distribution is common. The number at a pole varies from 14 to 21. Lagging and misdividing univalents, telocentrics, bridges with and without fragments are present.
On average 29.6 chromosomes pair at metaphase-I, while 5.4 remain as univalents. This point, coupled with the karyotypic evidence, makes it reasonably clear that there are probably two sets of 14 fairly homologous chromosomes plus 7 other chromosomes. In the former two sets, there are small portions that are homologous, which fact accounts for the low multivalent frequency. It appears that this race is a segmental-allopentaploid (AA AIAI B). On the basis of the comparative evidence from the karyotypes, it is proposed that this pentaploid race probably arose as a hybrid between triploid and tetraploid races in which unreduced gametes of former were involved.
The seeds appear to be inviable but the race is perpetuated by production of 8-10 bulbs by each individual.
