Grape Genetics Question

[reed]

I'm guessing that about 90% of my Concord and 95% of my Niagara grapes have been ruined by the various rot and fungus diseases that seem to be worse every year. I know that grape vines can throw a sport, I think it's called that, where a bud is genetically different from the rest of the plant. If that happened though I would expect all the grapes in a cluster or rather all the clusters on a branch to be different from the rest.  That however isn't the case, instead there might just be one or two grapes in a bunch that didn't rot. 

Is it possible there is a genetic difference in those individual grapes that would make it worthwhile to sprout their seeds?

[darrenabbey]

Theoretically, yes... but I wouldn't bank on that strategy. I'd wager growing a batch of seedlings from any of the plants would show a great deal of diversity, potentially in the resistance traits you're talking about. Those vines are clones of hybrids.

[Marches]

Jul 16, 2015 11:09:17 GMT -5 reed said:

I'm guessing that about 90% of my Concord and 95% of my Niagara grapes have been ruined by the various rot and fungus diseases that seem to be worse every year. I know that grape vines can throw a sport, I think it's called that, where a bud is genetically different from the rest of the plant. If that happened though I would expect all the grapes in a cluster or rather all the clusters on a branch to be different from the rest.  That however isn't the case, instead there might just be one or two grapes in a bunch that didn't rot. 

Is it possible there is a genetic difference in those individual grapes that would make it worthwhile to sprout their seeds?

I presume you mean botrytis. And no, those individual grapes probably aren't resistant, they either just didn't crack or didn't get it by chance.
I'd look at introducing crack resistance and botrytis resistance.
Crack resistance can be found in some varieties such as Vanessa. Cracking happens when there's been very dry weather followed by a lot of rain, the berries swell too fast and burst then rot (botrytis) gets in.
Botrytis will also infect grapes with thin skins and high sugars (since sugars feed the fungus), so varieties that aren't as sweet aren't as suceptible. Most table grapes have lower sugars than wine grapes anyway. It's almost always the very sweet varieties of grapes that are the most prone to botrytis rot.
Those varieties should throw out lower sugar seedlings anyway as their dominant species ancestor (Vitis labrusca) is low in sugars.

[reed]

I don't think they crack, it more starts with just a little black spot with a circle around it and soon consumes the whole grape. Sometimes they dry up that way and if you touch them a little puff of spore dust comes out. I don't ever remember not seeing it even as a kid but used too it wasn't so totally devastating. It didn't happen every year and when it did it didn't get them all. Rarely see it on the wild grapes but sometimes.



I googled botytis and from the pictures definitively not it although I have seen that once and a while. Looks more like below, the web site with this picture says it is anthracnose. Only on mine for the last several years  they nearly all look like the one on the right.