Sowing Vengeance: The Eldest Son's Disgraceful Green Thumb

Disowned, disgraced, and doomed to be a farmer. Being "blessed" with a farmer affinity is practically a death sentence for Chris Sparring. It's nothing close to the sword-wielding class he'd been raised to inherit, that's for sure. To make matters worse, his twin brother receives the affinity of a sword god instead, and wastes no time funneling years of jealousy into an attempt on Chris's life. With nothing left to lose, Chris must find a way to make it on his own and avenge his name. And this "useless" poison resistance of his may be just what he needs to turn the tables!

(Source: J-Novel Club)