Right now, it has no white feeder roots.
It might have had them, but when you pulled the rose out of the potting mix to look, those roots may have dropped off.

Those roots you see are woody roots. A two or three year old rose has to have them, but they do nothing to get a rose growing in spring. The feeder roots will need to (re)grow on this rose, and then the buds will swell.

Replant it, put it in partial shade (under a chair or table) and water it when it dries out at the roots.

Is this own root because I don't see an obvious bud. The left cane is dead at the base and needs to be cut off at that point and the right cane is also dead at the base I believe. I think it needs to be cut from the dark down to the wood if necessary and hopefully new growth will come from that point. If it is a grafted rose you will be cutting back to the graft. It has good looking roots so it should come back well. Good luck.

Thank you so much for your reponses ann and henry. This is a 1 year seedling, own root. I guess I should have left it alone, I have no patience whatsoever.

You know that since this is on its' own roots you can prune this down as far as you want. It is a first year seedling that appears to have canker at the base which you should have realized. You shouldn't have dug it up. There is no point ever trying to save questionable cane. You could replant it and treat it like a cutting and it should come back well for you.

I don't think this is canker. I believe this is just color change close and under the soil line. I wouldn't prune anything from this one. Just plant it back and be patient.
Olga

I'm not sure if it is canker or not. If it is canker, it looks like the whole plant is infected so you might as well leave it alone and if it spreads then try to cut off any of the infected areas.

I agree. Don't cut the canes off yet. Plant it and leave it alone. The almost invisible feeder roots fall away with the soil or potting mix each time to check the roots.
You should do something to keep the canes from drying out. If potted, place a clear plastic bag over it and tie it tightly at around the pot. Make sure the soil is moist but not soaking wet. The plastic bag will act like a greenhouse, keeping the canes moist as the moisture condenses and the air inside the bag becomes saturated with moisture. Place it in light shade so it doesn't get too hot in the bag. After leaf growth appears poke a few holes in the bag to allow the canes to harden off. After it appears to be growing well plant it in the ground without losing the soil on the roots.
To plant a potted rose without losing the soil from the roots, cut the pot on opposite sides. Tie the pot together at the top and half way down. You can also use rubber bands or masking tape to hold it together. Have tthe hole prepared and make it twice as wide as the pot. Just before planting cut the bottom loose from the pot and leave it to help keep the rose from falling out the bottom. Place the potted rose in the hole and slide the bottom out from under the pot. Pull the soil into the hole up to the middle piece of string/masking tape/rubberband. Cut the string/masking tape/rubberband on both sides and continue filling the hole until you reach the top string/masking tape/rubberband. Cut it and continue filling the hole until just the tips of the pot are showing. Pull the cut sides straight up and dispose of them. Your bush won't know it's been moved. Water well, deep, and often until the bush is growing good. Unless you plant in clay, you can't water a new rosebush too much.
If you plant the rose directly into the ground cover the canes with a mound of soil to keep them from drying out. After growth appears from the soil mound, you can gentle wash it away or as I do, leave it for Mom Nature to handle.

I have the same problem. It took me nearly a year to find out the problem. Rose like dry root. On the label when you buy a rose it should say somethings like "well drain soil". Potting (soil) rose shouldn't be water often. It hold a lots of water which rotting the root system. Try to plant it in the ground with no top or potting soil. Mix the dirt with some sand. Mulch it and let nature do the rest.( on yeah try to water it when you think it is too dry)

I've had a few look like this this Spring and I attribute it to a late freeze that surprised the weather guys, and me.
The Roses involved had all started to leaf out-Zappo a hard freeze.
The black at the base marched right up the canes and none of them have survived.
I hope that's not the case with your Rose, so I say replant it, water it and wait.
You'll know soon enough.

What Olga and anntn said. :-)