|
|
Post by frogsleapfarm on Feb 18, 2010 23:22:10 GMT -5
Most/all of the genotypes used as rootstock for greenhouse production trace to hybrids between esculentum and hirsutum. Has anyone grown these for fruit? I'm thinking of making a backcross to a great heirloom this summer to capture the disease resistence in hirsutum, but I'm too old to be chasing a multi-year project if the hybrid is just too "wild". Any advise out there?
|
|
|
|
Post by gobmaters on Mar 10, 2010 18:19:15 GMT -5
Don't bother to do this unless you expect to live a long time and want to be frustrated along the way. The hirsutum hybrid rootstocks were originally developed in Holland(DeRuiter) for use with greenhouse varieties to help overcome soilborne problems. They are likely a cross between an esculentum female with fusarium crown rot and TMV resistance x a hirsutum line that has a lot of resistance to soil borne diseases and imparts a lot of vigor to the scion variety. These rootstock lines are probably self incompatible so that you can't self them to produce seed and can only be crossed to cultivated tomato if you use the cultivated esculentum type as the female parent. I have spent some time trying to get both early blight and late blight resistances from hirsutum into cultivated tomatoes and have ended up with only moderate resistance, which in the case of late blight is not very useful. The primary gene I am aware of that has come from hirsutum and is in cultivated tomato is the dominant B gene for beta carotene (orange fruit color). Other traits from hirsutum tend to be controlled by several genes, and the breeder has to give up a lot of the level of the original trait because of linkage to deleterious traits, which are difficult to break. Also, backcrossing to esculentum and getting a smaller plant with much less vigor and a heavy set of large fruit tends to dilute the level of trait expression coming from hirsutum. I hope this is helpful and will spur more discussion on this topic.
|
|
|
|
Post by frogsleapfarm on Mar 11, 2010 11:52:11 GMT -5
Thanks, my concerns are confirmed. I'll focus my limited time on other projects.
|
|
|
|
Post by frogsleapfarm on Mar 11, 2010 12:25:52 GMT -5
I definitely think this would help, and perhaps some of the pathogen resistance genes have been mapped to specific hirstum chromosomes. I am particularly interested in Septoria tolerance, which has not been mapped, and is probably specific to individual hirstum lines. The Cornell folks are now well along in introgressing this resistance into commerical lines
|
|
