i am a total beginner in this. i just wanted to know, can you cross a triploid with say a tetraploid rose–for instance a bourbon rose with a hybrid tea or portland rose–and will it make a successsful cross in spite of the difference in the chromosome count. and if so can someone explain the ploidy count Thanks looking forward to your reply
Yes! Interploidy crosses are possible and are made frequently. There are a lot of modern triploid triploid shrubs people are using as parents especially these days. The three sets of chromosomes in triploids typically do not divide to gametes in complete sets. When there is plus or minus some chromosomes and lack of complete sets of chromosomes in an egg or pollen grain, they usually abort. The rarer gametes that are fertile in triploids have complete sets of the 7 chromosomes of rose. The number of sets can be 1, 2, or even 3 usually. Your offspring from interploidy crosses can vary across seedlings for ploidy depending on the ploidy of the gametes that came together to make them. I have made interploidy crosses and documented offspring ploidy in some crosses. Here is a link to that article. http://www.globalsciencebooks.info/JournalsSup/images/0906/FOB_3(SI1)53-70o.pdf