Backcrossing and F2s

**Patrina_Pepperina** · March 7, 2006

This past weekend, several Tomato folk got together in Marysville Victoria for a tomato tasting, and Ray (Raymondo), Craig (Kionga) and I discussed backcrossing as a way of hastening the process of finding what you want out of a cross. This was in particular reference to the Dwarf project between north and south hemispherers. Craig brought up the idea with me as we travelled to Marysville. Ray suggested that it might be a good idea to back cross at the F2 stage.

I'm thinking that it might be a good idea too, especially with the cross that turned out to be 3-way, ie. Bashful (GDC x [Orange Strawberry x unkown] which had a smallish semi heart shape red F1). I suspect that it's going to be difficult to find large fruited segregates out of this one.

The other issue (besides backcrossing) that I'd like to know more about is how likely it is to get a large fruited F3 from a smaller fruited F2? This year I had larger globes on an F3 than on the F2 last year for a cross between Earl of Edgecombe and Maritza Rose, but maybe that's just environmental.

I'm also wondering whether it would be a good idea for a great tasting F2 (that might not have the size we want) to be backcrossed with the larger original parent.

Are the gains greater than the losses when backcrossing? I imagine it might broaden the project but maybe it could also shorten it somewhat?!

Patrina

March 7, 2006	#1
Patrina_Pepperina Cross Hemisphere Dwarf Project™ Moderator Join Date: Jan 2006 Location: New South Wales, Australia Posts: 3,094	Backcrossing and F2s This past weekend, several Tomato folk got together in Marysville Victoria for a tomato tasting, and Ray (Raymondo), Craig (Kionga) and I discussed backcrossing as a way of hastening the process of finding what you want out of a cross. This was in particular reference to the Dwarf project between north and south hemispherers. Craig brought up the idea with me as we travelled to Marysville. Ray suggested that it might be a good idea to back cross at the F2 stage. I'm thinking that it might be a good idea too, especially with the cross that turned out to be 3-way, ie. Bashful (GDC x [Orange Strawberry x unkown] which had a smallish semi heart shape red F1). I suspect that it's going to be difficult to find large fruited segregates out of this one. The other issue (besides backcrossing) that I'd like to know more about is how likely it is to get a large fruited F3 from a smaller fruited F2? This year I had larger globes on an F3 than on the F2 last year for a cross between Earl of Edgecombe and Maritza Rose, but maybe that's just environmental. I'm also wondering whether it would be a good idea for a great tasting F2 (that might not have the size we want) to be backcrossed with the larger original parent. Are the gains greater than the losses when backcrossing? I imagine it might broaden the project but maybe it could also shorten it somewhat?! Patrina