If one pollen mother cell on an anther produced ~ 4 pollen cells …
… then how many pollen cell(s) does it take to produce 1 seed in a hip ? One pollen cell equals one downcomer pipe equals one seed or more ?
(Assuming everything in between pollen cells being generated by mother cell and seed created works tickadeeboo).
Easyiest answer so far to follow
From lndia google source “Vedantu” …
“ The sexual reproduction in rose plants happens with the fusion of male and female gametes produced by plants.
The male gametes are produced by the process of microsporogenesis which occurs in anthers ….
… whereas the female gametes or eggs are produced in the ovary of the flower.
… After the maturation of gametes, fertilization between gametes occurs by pollination in which the male gametes reach the female gamete (“my downcomer style tube in pistil to ovaries”) for fertilization to give rise to a new rose plant.”
… appears by my conjecture from the semantics intent of english text that it takes multiple mature males gametes (and associated style tubes?) from anther pollen cells (gametes eventually) to fertilize one female gamete, to make 1 seed.
Why ? Writes male gametes as plural, female gamete singular … hmmmm? Maybe 9 out 10 duds ? Still only one down the style to ovary female gamete wins?
Looks like until semantic clarity that l pound the pollen ( pollens cells and eventually male gametes-from anther collection to the stigma).
Gets tough and rationing imposed when little pollen produced/ collected. Anyways how l see it today … until torrow.
Also learned why wait awhile with collected before applying anthers - euphemistically called drying? Really waiting until number of developed male gametes from available pollen cells has hit a near maximum - nope l don’t believe that means wait days, they are in a hurray to develop.
I wait no more than a few hours to 24 hours before applying until proven wrong. I find a sticky stigma doesn’t stay so for long after the bloom opens and end up watching the pollen gametes tumble off it. Thats when the salvia is applied to stigma and hope it doesn’t prevent the male gamete from boring down the style because of entrained initial digestive enzymes.
It just takes one pollen grain to result in a seed, but two sperm cells are produced and released–only one of them actually fertilizes the egg. Recommendations to apply pollen heavily and over more than one day (if possible) come mostly from experience that it tends to result in more seeds. That might very well be due to large percentages of poor-quality pollen or incompatibility issues.
Many plants will have receptive stigmas a bit before the flower actually opens, so you might be able to expand your pollination window a little that way.
Stefan
Just for fun, I decided to ask ChatGPT your original question (minus the last line). The answer was pretty good! Maybe I should spend more time watering in our ongoing hot drought (just survived four more days in a row at or above 101°F/38°C, plus humidity–I never thought that “moderating” to 90°F would feel like such a relief) and farm out my responses to RHA questions to ChatGPT instead 
Stefan
Never thought of that tool. I try it one day but only with VPN.
We are (domestic users) as of today - officially allowed to use a hose with trigger nozzle to water gardens and lawn - no sprinklers. Thats only one day a week for one hour if l read stage 2 promotion from stage 3 - 3 was only carry buckets to garden.
Which was a promotion from 4 which was no outside watering, min flushing, only 3 min showers etcetc…
A main 6 foot diameter feeder pipe failed about 4 weeks ago. Engineers said pipe would last 100 years … lasted 50.
Surprisingly one of the best blooms in years, grass a little toasted.
38c too hot especially with eastern humidity.
This latest heat wave on prairies peaking at 35C next Wednesday - but no real humidty - but Banshee still balls. I couldn’t even hack heat and humidity 30 years ago at only O Hare when went outside. Like crashing into a wall.
Love Prairie’s hot but dry.
Downloaded and yes this thing is a huge leap forward in getting info for review and acceptance … quickly. Now know apparently male gametes “r” the pollen … feel empowered already. Just have to recognize dud info.
Feels like my far wasterly info was already an AI as very similar wording …