Disease resistance testing

Boutique Tomatoes · February 17, 2013

I've been doing some reading and thinking on this subject for a while. I have relatively little disease pressure currently, but want to include planning for it in some of my breeding projects.

Marker testing 100's of plant tissue samples is out of the question. I don't have the equipment and grad students to do it, or a budget based on the idea of a future profit from my projects.

Large scale field planting in areas with disease pressure seems to be a common option, selecting plants that appear to have resistance that way. But that takes a while and a lot of space and assumes that the plants are uniformly exposed to the disease you're trying to select for resistance to. Sounds like a lot of work, a lot of time and rolling the dice.

I've read some articles where individual leaves where exposed to isolated strains of the disease in question in a growth chamber and the plants that provide leaves which appear to be infected are culled and the remainder allowed to fruit for further selection.

This kind of approach seems most likely to work for the independant breeder to me. My current thinking, using something where I would be looking for disease resistance is to start several hundred seedlings of a candidate line in cell packs. Once they're at about a 4 week size place them in an isolation chamber where I can maintain a fairly high humidity built from left over polycarb pieces from my greenhouse project. Blend samples of infected plant material with distilled water and spray the seedlings, then observe for a couple of weeks. What lives goes forward.

Not exactly cutting edge, but I think it should work. It would be a bit haphazard compared to using DNA testing or innoculating plants with isolated strains of a disease causing agent, but you could cheaply and easily test 100's of F2's this way.

Anyone have an opinion?

February 17, 2013	#1
Boutique Tomatoes Tomatovillian™ Join Date: Feb 2011 Location: Northeast Wisconsin, Zone 5a Posts: 1,109	Disease resistance testing I've been doing some reading and thinking on this subject for a while. I have relatively little disease pressure currently, but want to include planning for it in some of my breeding projects. Marker testing 100's of plant tissue samples is out of the question. I don't have the equipment and grad students to do it, or a budget based on the idea of a future profit from my projects. Large scale field planting in areas with disease pressure seems to be a common option, selecting plants that appear to have resistance that way. But that takes a while and a lot of space and assumes that the plants are uniformly exposed to the disease you're trying to select for resistance to. Sounds like a lot of work, a lot of time and rolling the dice. I've read some articles where individual leaves where exposed to isolated strains of the disease in question in a growth chamber and the plants that provide leaves which appear to be infected are culled and the remainder allowed to fruit for further selection. This kind of approach seems most likely to work for the independant breeder to me. My current thinking, using something where I would be looking for disease resistance is to start several hundred seedlings of a candidate line in cell packs. Once they're at about a 4 week size place them in an isolation chamber where I can maintain a fairly high humidity built from left over polycarb pieces from my greenhouse project. Blend samples of infected plant material with distilled water and spray the seedlings, then observe for a couple of weeks. What lives goes forward. Not exactly cutting edge, but I think it should work. It would be a bit haphazard compared to using DNA testing or innoculating plants with isolated strains of a disease causing agent, but you could cheaply and easily test 100's of F2's this way. Anyone have an opinion?