Why are my hips turning brown and failing

I had about 40 crosses that were developing nice hips. All crosses were done in June and they all were showing nice plump hips. Then all of a sudden the stem of the hip started to turn yellow then brown and the hip turned brown as well. Has happened to about 20 of them so far. Plants are all healthy no sign of any disease. We did have two weeks of very hot weather (high 90’s) and the plants were well watered. When I open the shriveled hips I see plenty of nice size seeds. Anyone have any ideas why there are so many failures? Any help appreciated.

Could be any number of reasons but usually it means there are no viable seeds. Having seeds in a hip doesn’t mean the seeds have embryos in them. Seeds do sometimes develop without embryos. Could also be there were larvae in the seeds that ate the embryos or a fungus that killed the embryos or a fungus that is infecting the hip or a bug that is infecting the hip or just plain genetic incompatibility.

List your crosses here and maybe there are others with whom you can compare notes. Post some pictures of the hips but also of the leaves and canes and plants.

Keep plugging at it. I see that you are in Massachusetts. I’m just over the line in Connecticut. IMHE a fungicide rotation schedule will improve your results immensely if you aren’t already spraying.

My crosses were as follows, I’m always confused about if it should be seed x pollen or pollen x seed so below I am showing them as seed x pollen
Fragrant Cloud x Olympiad
Medallion x Paradise
Chicago Peace x Olympiad
Miss All American Beauty x Blue Girl
Blue Girl x Midas Touch

All of these are classic hybrid tea roses which are predisposed to have empty seeds and all of which are disease magnets. You don’t say if you are spraying but if you plan to keep up with those breeders in your stable then you must do so. In fact, any rose is going to be a disease magnet in your neighborhood.