Induced colchitetraploids in allium cepa L.

Abstract

Polyploidy was induced by colchicine in Allium cepa L. Five plants of Allium cepa (AC1-AC5) were isolated from the 0.2% colchicine treated inflorescences. The meiotic stages were analyzed in treated buds. Various cytological features like chromosomal associations (quadrivalents, bivalents and univalents), chiasmata frequency and terminalization coefficient were recorded at diakinesis/ metaphase-I. Anaphase/telophase-I/II were studied in all the cholchitetraploids. In all these plants, the anaphase/telophase-I were abnormal showing unequal distribution, laggards, micronuclei and multipolar at telophase-II. Pollen mitosis was studied in these plants. The chromosomes (n=16) were found at metaphase. Pollen fertility was low (40.9 to 56.9%) in all colchitetraploids.