If you know how to preduce hybrid seeds this should be easy. Find a happy lamp flower (you can find them in the summer) go to tartan (the hybrid plant) and give him the flower together with a seed. If you put in the flower and a tomato seed he will spit it out and say its a normal tomato seed but it's not! You can plant this seed any season you want so if you have a sweet patota and you give it to tartan with a happy lamp flower you won't just be able to plant it in fall but also in winter, summer and spring.