There is often not one single method to determine the basic chromosome set of a species for certain. In general you use several methods and draw a final conclusion by using the results of all available methods. And it is a matter of which methods you can use in your lab.

If you have a segregating population you may use following methods:

- Maximum number of SSR-alleles

- Linkage mapping, especially with SSR-Markers

- Ratio singledose/multidose markers

- Ratio of markers in linkage/repulsion coupling

Have a look at this paper:

https://www.researchgate.net/publication/275018496_Analysis_of_a_Complex_Polyploid_Plant_Genome_using_Molecular_Markers_Strong_Evidence_for_Segmental_Allooctoploidy_in_Garden_Dahlias

kind regards

Stephan

@ Stephan Schie

Thanks, please suggest if I can do it without molecular techniques.

I think this is not possible for a plant with so many chromosomes. You could analyze the multivalents during meiosis but this is no certain indication. Another indication could be the inheritance of phenotypic traits.

If you would have specific probes you could think about FISH and GISH. If the chromosomes would be very big it could be, that one can seperate the chromosomes by flow cytometry like as for wheat.

But for a plant with so many chromosomes this should not be possible.

@ Stephan Schie

Thanks

Hello Sir,

Hope, it would be helpful.!!

Base number represents the lowest known ancestral chromosome number in the haploid complement of a species and is designated by letter ‘x’. In angiosperms, the base number ranges from as low as x = 2 in Haplopappus to as high as x = 43 in some species of family Winteraceae.

In order to estimate the base number, many approaches were employed (Otto and Whitton 2000). Stebbins (1958) opined that a species can be considered polyploid if its haploid chromosome count is a multiple of lowest one of that particular genus.

In recent times, base number can be determined by new methods, for example, parsimony principle (Hansen et al. 2006; Timme et al. 2007) and probabilistic approach (Mayrose et al. 2010).

While sorting base number of a particular genus, numerous things are to be remembered, for example, least chromosome counts, levels of polyploidy, besides giving weightage to most successive chromosome number.

Regards

MA Khah

[Note: The answer is a part of my thesis]