Q. What do you understand by Chromosome Behaviour?

When we study meiosis. we not only observe the regularity of pairing which is important' for' the fertility of the plants, we are also able to make a chromosome to chromosome comparison. This provides valuable information about the role of chromosomes in heredity. Taxonomists use this information to understand relationships amongst different species of plants. We can also determine the nature of the genome to find out if it is homozygous or heterozygous. Genome analysis in plant taxonomy has been particularly useful in understanding polyploidy add for establishing the parentage of polyploids. A very significant study in this regard is the case of the common hexaploid bread-wheat, Triticum ;aestivum. The genome of this economically important plant has been designated as AABBDD with 2n = 42 chromosomes. Detailed genome analyses have established that 3 diploid species have configured to the evolution of this hexaploid wheat. The A genome is from the diploid Triticum monococcum (2n = 14), the B genome is from a wild grass Aegilops speltiodes (2n = 14), and the D genome has been contributed by Aegilopssquarrosa (2n = 18).

Finally, we must remember that as with any other character, the value of 'cytotaxonomic data depends upon the group or category ,under investigation. A combination of cytological information with data from other disciplines will provide 'a more useful tool to the taxonomist.