What are planted to grow seedless fruits?

copied straight answer, feel free not give me credit!

plants have ability cross fertilize , produce sterile offspring mammals do. think mules. since fruit product of flowers reproductive center grows around seed after pollination. if no mature seed develops fertilized egg considered seedless. many times immature seeds present ignored black specks in bananas or soft, shriveled, white things in watermelon. grow more plants have use same parents or vegetatively clone seedless cultivar.
seedless crosses occur naturally dead end lack of next generation except humans have been used plants provide support in creating subsequent generations. nice case of symbiosis. eat seedless fruit plant continues , spreads.
seedless watermelons have been since 1939. occur because of plants can do. plants can go diploid tetraploid. 2 set of genes 4 sets. has occurred spontaneously throughout history can induced in lab now. if cross diploid tetraploid mule in same way jack donkey covering mare produces mule. chromosomal pairs cannot align during meiosis normal sequence unimpaired mitosis mule or triploid plant can grow cannot produce next generation. since triploid plants can’t produce gametes next generation pollinated diploid father plants. act of pollination triggers fruit grow without fertile egg present.
in 1876 scottish immigrant william thompson developed seedless grape still call thompson grape. had come natural process, mutant diploid seedless grape growing wild. discovered , propagated humans grafting cuts onto other rootstocks. thompson continued grafting until developed line still use. same true of seedless oranges. graft descendants 1 wild, seedless plant.
seedless plants dependant on humans propagation alternated means.

Science & Mathematics Botany Next