what is autopolyploidy?how does colchicine induce polyploidy?name an autopolypioid that has succeeded as a variety?
When a cell is having more than two paired sets of homologous chromosomes, the condition is known as polyploidy. Autopolyploidy is a phenomenon where one or more extra sets of chromosomes occur due to mutation at the time of cell division.
Colchicine prevents the formation of spindle fibers during cell division. As a result there is no movement of chromatids in anaphase and they settle inside the single nucleus forming an extra set of chromosome.
Seedless watermelon is an example of polyploidy that has succeeded as a variety.
AUTOPOLYPLOIDY:- it is a type of polyploidy in which there is a numerical increase of the same genome, e.g. autotriploid (AAA). some of the crop and the garden plants are autopolyploid s e.g maize, rice, gram.
COLCHICINE can induce polyploidy in polyploids with odd number of genomes (i.e. triploids pentaploids) are sexually sterile because the odd chromosomes do not form synapsis. they are therefore, propagated vegetatively e.g. banana pineapple. polyploids also do not cross bred freely with diplods.It appears to have a twofold function: the stimulation of the nuclear division and of cytocinesis, followed by induction of polyploidy.