"Am I supposed to just let that out into the world for everyone and lose all that hard work?"
There's a lot to unpack here:
".../lose/ all that hard work..."
There are a couple of ways to look at this:
<Ghandi> Huzzuah the whole world is now going to benefit from all that 'hard work'!
<Buddah> Huzzuah the whole world is now going to benefit from all that 'hard work'!
<MotherTeresa> Huzzuah the whole world is now going to benefit from all that 'hard work'!
etc
v.s.
<Monsanto>"NOOOOOOOO OUR PROFITS, OUR SHAREHOLDERS, OUR WORLD DOMINATION!"
<AnyGreedyMFer> "NOOOOOOOOO my aspirations to dominate the planet and receive a royalty for ever seed planted or cutting took!"
"Am I supposed to just let that out into the world for everyone"
You gotta really look at yourself asking that kind of question. Are you Martin Shkreli selling your pill that used to be $13.50 yesterday for $750 today that people will actually die if they don't get or can't afford? Banking on insurance's deep pockets to get paid all the while neglecting the individuals who can't afford or have been denied insurance due to pre-existing conditions...
[hypothetical you, not 'actual' you; don't take this as a personal attack, I'm sure you're a good person]
If you think you've got any "right" to sell your mite resistant seed for $750 a seed instead of $13.50 a seed, prosecuting adjacent farms for growing 'your' crops that you've made deliberate effort to spread to their property without being asked to... I personally think you 'aught to be kicked into a wood chipper along with anyone on your will who is bequeathed that intellectual property.
If you want to try to counter that with, "It's not insulin, you're not going to die if you don't by my seed, you're just going to spend more money fighting pests" you're still making an argument from the side of the fence most people would call "evil".
If you come from the argument point of, "I've made such a significant discovery the entire planet needs to benefit from, here is that work, and no body or entity is allowed exclusive rights or privilege to produce this product the entire planet is going to benefit from. Here is my donation bin, give what you feel is appropriate or can afford to part with" You're more than likely going to get a bunch of tax-exempt money, maybe [probably] enough, to never have to farm again for the rest of your life. It's almost a guarantee to see hundreds of thousands of dollars from entities struggling to get the public to forget about their past transgressions; their negative karma turns into your positive karma.
"Should that not also be intellectual property?"
I would argue it still /should/ be intellectual property, that being said, you do realize that filing for a patent on said IP means you have to /disclose the sauce/ to the patent office which google will now put on the internet which now allows any black market/counterfeit operations to occur in nation states with no extradition treaties (.cn/.ru) with the united states. You put that mite resistant strain out there and guess what, people with more resources than you are /already/ taking 'your work' and producing it at a volume you could /only dream of doing/ with no fiscal budget to even attempt any litigation efforts should they even be possible. You're talking about entities that routinely have vans pull up to intersections to have individuals kicked into them, driven off somewhere to never be seen or heard from again.
You can't have it 'be a secret' and have it 'be patented' at the same time.
You /can't/ expect to be the sole benefiting entity from a discovery that's supposed to benefit the entire planet.
Lets also be real here, if you don't discover this mite resistant gene in your $x,xxx garage lab, someone working in monsanto/dow/bayer/etc's $xx,xxx,xxx++ laboratory /will/ discover it. It's kinda your responsibility to make this information is available to and FOR everyone before someone decides that this information is to only benefit themselves and their shareholders.
so back to:
"Am I supposed to just let that out into the world for everyone"
ABSO-FUCKING-LUTELY. If you don't share it with everyone someone who is working for someone whose company has absolutely zero altruism or sense of obligation to anything but their share holders will see to it that only Monsanto benefits from it.
Should the chemist or botanist or geneticist who came up with the discovery get paid?
They SHOULD but if you look in practice any of the chemists who came up with materials of the future in the 20th century didn't make billions or millions of dollars, they got paid their annual salary, because they signed a document when they got hired that any of their discoveries are property of the company they work for, not their own property.
Basically if you're looking at GMO with the intoxication of affluence you've let your pupils dilate to the shape of dollar signs, and that's bad.
The way IP law centers around GMO is heavily skewed towards monolithic entities, which means if you think your discovery is going to turn you into one of these monoliths over night you're going to be sorely disappointed when they steal your work and file the paperwork to own it; the same paperwork that was too expensive for you to file yourself.
Bascially, don't act like the dick who made starlite
https://en.wikipedia.org/wiki/Starlite
because some company will own your IP after you die.