Keep them moist and put them outside before the new growth gets much more advanced. The fact that you appear to have them indoors as well as that part of the peat based medium you have planted them in appears not to have been moistened all the way through are much more concerning than the lack of sprouting all the way to the top of each cane. All the more so because the production facility probably cut them off using a band saw - as they will have done to thousands of other specimens. Rather than having pruned each one selectively using hand shears.

Roses are easy to grow once they are established. In recent years, I have had trouble with roses purchased from garden centers that would not grow when planted out. This may be because the plants were held too long in storage before coming to market. It is also imperative when first planting roses to frequently sprinkle the canes to avoid them drying out. Desiccation is a common killer of freshly harvested roses. Once buds “pop” and shoots emerge, culture can continue as with any garden plant providing appropriate moisture as needed. Fertilization should follow recommendations of your soils analysis.

The contrarian rosarian–debunking rose mythology – The Garden Professors™

thanks for commenting. it was outiside but I brought it inside because it was raining so stormy . I was scared rain would damage it more. I will bring it back when rain stops. what should I do now ? should I spray on them with fungicide?

No, don't spray with fungicide. :) There's really nothing wrong with your rose. If you're worried about that cane, then cut it down to the next leaf node about 1/4" above it at a slant.

aww ❤️thanks for relieving me

It’s good that you paid attention to the black parts at the tips of the canes. Just trim down below the black parts to prevent them from spreading down the canes and your roses are fine. It is a small issue when you discover it early and take care of it right away. I had to do this a few times to one of my David Austin roses this year, too. Helen

I'm scared to prune. because sometimes the blackened parts come again back after pruning . how actually should I prune so i get rid of them fully?

Here is a good read for you https://www.gardeningknowhow.com/ornamental/flowers/roses/rose-canker-fungus.htm 

Disinfect your pruners, trim below the black part to the green tissue (detail info in the link above), then disinfect your pruners after you trim the diseased cane.

If the tips of the canes turn black again, do the same thing again. I had to trim my Emily Bronte bare root a few times this year and it is fine now. Helen

thank you very much . hope it doesn't show up again :(

Cut ends of canes almost always develop darkening (black), sections, starting from the cut edge, and continuing to just above the uppermost emerging new growth. The rose bush is shutting down that section and creates a safety barrier at where the green, live stem and dead, darkened stem meet, becoming a normal, healed stem end.

Moses

Why are you growing bare root roses inside? :-)

i grow them in balcony xD

i bring them inside when it's raining

You don’t need to do that, let them soak up the rain.

i lost 4 of my david austin roses because of rain. i didn't take them inside nd left them in balcony they soaked in water. even though they had good drainage but they died i heard that soil should be dry sometime so roots don't rot. finally i don't have them now.

OMG! We are praying for rain. Roses need rain.

but mine are in pot ..not in ground 😀 I wish i also had a garden

your pots would have had to not be draining at all in order to get root rot.

I think there was a misdiagnosis for your David Austin’s .

the black parts are fine, that is normal when you get a new bare root rose.

i Hope you are right. i hope it's not rose canker ❤️❤️ thank you so much for commenting

I have a ton of Austins in pots outside and it rains all summer here. Just make sure you have a good draining potting mix and holes in the bottoms of the pots for drainage. Roses love rain and its very healthy for them.

If you have to keep saucers under your pots, dump them out after the rain if you think they are too waterlogged. I dont keep saucers under mine but I know some people who balcony garden do.