Pankaj ji You are again confusing between N and X, that was my original correction that you did not realize.
A plant can either be N (gametic) or 2N (sporophytic), it can't be 2N, 4N, 6N, etc. it can be 2N=2X, 3X, 4X, 6X, 8X, etc., all except first one being polyploids -- Dr. Gurcharan Singh Retired Associate Professor SGTB Khalsa College, University of Delhi, Delhi-110007 Res: 932 Anand Kunj, Vikas Puri, New Delhi-110018. Phone: 011-25518297 Mob: 9810359089 http://people.du.ac.in/~singhg45/ On Sat, Sep 25, 2010 at 11:09 AM, Pankaj Kumar <[email protected]>wrote: > I have done experiments personally and they are not always sterile. I > had crossed 2n and 4n Raddish and got 3n sporophytic stage. > Thanks anyways. > Pankaj > > > On Sat, Sep 25, 2010 at 11:29 PM, Gurcharan Singh <[email protected]> > wrote: > > A plant with 3X in gametic stage, would become hexaploid sporophytic > phase > > 2N=3X may generally result from a cross between a diploid and a > tetraploid, > > and would be sterile and perish soon, unless it multiplies vegetatively, > or > > else duplication of chromosomes occurs to make it hexaploid, a phenomenon > > commonly seen in Senecio and Tragopogon. > > > > -- > > Dr. Gurcharan Singh > > Retired Associate Professor > > SGTB Khalsa College, University of Delhi, Delhi-110007 > > Res: 932 Anand Kunj, Vikas Puri, New Delhi-110018. > > Phone: 011-25518297 Mob: 9810359089 > > http://people.du.ac.in/~singhg45/ > > > > On Sat, Sep 25, 2010 at 10:51 AM, Pankaj Kumar <[email protected]> > > wrote: > >> > >> I imagine if it was a correction of addition. Anyways, just a > >> querry...So you mean to say a plant with 3x chromosome is not a > >> polyploid? > >> Pankaj > >> > >> On Sat, Sep 25, 2010 at 9:30 PM, Gurcharan Singh <[email protected]> > >> wrote: > >> > Pankaj ji > >> > A slight correction. Every plant has N (gametic) and 2N (sporophytic) > >> > chromosomes. Every plant has basic number X, usually same for a genus. > A > >> > diploid would have 2N=2X, whereas a polyploid would have 2N=4X > >> > (tetraploid), > >> > 6X (hexaploid), 8X (octaploid), etc. Plant is known as polyploid and > >> > phenomenon as polyploidy. > >> > -- > >> > Dr. Gurcharan Singh > >> > Retired Associate Professor > >> > SGTB Khalsa College, University of Delhi, Delhi-110007 > >> > Res: 932 Anand Kunj, Vikas Puri, New Delhi-110018. > >> > Phone: 011-25518297 Mob: 9810359089 > >> > http://people.du.ac.in/~singhg45/ > >> > > >> > > >> > On Sat, Sep 25, 2010 at 6:59 AM, Pankaj Kumar <[email protected] > > > >> > wrote: > >> >> > >> >> Usually the chromosoe number is 2n or diploid, when an organism has > >> >> more than two sets of chromosomes then they are called polyploid and > >> >> the phenomena is called Polyploidy. > >> >> It is not a very uncommon phenomena in plants. Highest polyploidy is > >> >> found in ferns. Orchidaceae is supposed to be one group with high > >> >> polyploidy too. > >> >> Regards > >> >> Pankaj > >> >> > >> >> > >> >> > >> >> On Sat, Sep 25, 2010 at 7:17 PM, promila chaturvedi > >> >> <[email protected]> wrote: > >> >> > Dear All, > >> >> > I want to know what is Polyploid and Polyploidy. This is > >> >> > usuall occurance in > >> >> > Passifloras, but can bein other plants as well. > >> >> > Promia > >> >> > >> >> > >> >> > >> >> -- > >> >> *********************************************** > >> >> "TAXONOMISTS GETTING EXTINCT AND SPECIES DATA DEFICIENT !!" > >> >> > >> >> > >> >> Pankaj Kumar Ph.D. (Orchidaceae) > >> >> Research Associate > >> >> Greater Kailash Sacred Landscape Project > >> >> Department of Habitat Ecology > >> >> Wildlife Institute of India > >> >> Post Box # 18 > >> >> Dehradun - 248001, India > >> > > >> > > >> > > >> > > >> > > >> > >> > >> > >> -- > >> *********************************************** > >> "TAXONOMISTS GETTING EXTINCT AND SPECIES DATA DEFICIENT !!" > >> > >> > >> Pankaj Kumar Ph.D. (Orchidaceae) > >> Research Associate > >> Greater Kailash Sacred Landscape Project > >> Department of Habitat Ecology > >> Wildlife Institute of India > >> Post Box # 18 > >> Dehradun - 248001, India > > > > > > > > > > > > > > -- > *********************************************** > "TAXONOMISTS GETTING EXTINCT AND SPECIES DATA DEFICIENT !!" > > > Pankaj Kumar Ph.D. (Orchidaceae) > Research Associate > Greater Kailash Sacred Landscape Project > Department of Habitat Ecology > Wildlife Institute of India > Post Box # 18 > Dehradun - 248001, India > -- Dr. Gurcharan Singh Retired Associate Professor SGTB Khalsa College, University of Delhi, Delhi-110007 Res: 932 Anand Kunj, Vikas Puri, New Delhi-110018. Phone: 011-25518297 Mob: 9810359089 http://people.du.ac.in/~singhg45/
