ISHS Acta Horticulturae 433: I International Symposium on Edible Alliaceae
INTRASPECIFIC GENETIC DIVERSITY IN ALLIUM ASCALONICUM |
| Authors: | K. Talukdar, S. Sen |
| Keywords: | shallot, karyotype, cytophotometry, colchicine, in vitro response |
| Abstract:
Cytological study of the genus Allium has revealed considerable inter-and intra-specific variation. Chromosome architecture, nuclear DNA, response to chemical agents as well as in vitro response are utilised as parameters for measure of genetic diversity. In the present study these criteria were applied to determine the genetic variability of two variaties of Allium ascalonicum L. (the commercial shallot of USA and Europe), also regarded by some authors as a horticultural form of A. cepa L. The karyotype analysis showed gross similarity in chromosome structure. The in situ estimation of nuclear DNA by Feulgen cytophotometry and statistical analysis of variance of the data showed a significant difference in the 4C DNA content of the two varieties. The period of treatment required for induction of polyploidy in roottip cells by colchicine differed in the two cultivars. The difference in the amount of nuclear DNA between the two varieties of shallot could indicate that this alteration might have played a role in bringing about genetic diversity in this species. However the two cultivars showed more or less identical response in in vitro growth. Bulb multiplication was obtained in Murashige and Skoog medium with BAP supplement, contrary to the tendency to normally form single bulb per seed in the field. Stable diploid regenerants too were obtained via callus culture from bulb scales in MS medium supplemented with 2,4-D, IAA and kinetin. As such the tissue culture method adopted here provides an economic and rapid method of shallot proliferation even during the off-season. | |
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