无籽西瓜的育成,有近50年的历史,是用四倍体西瓜和二倍体西瓜杂交制种,长成苗子,结出西瓜是无籽,原因是因为两种西瓜染色体数目不同,精卵结合不能配对,正像马和驴配生骡子,而骡子再不能生育一样。因为四倍体西瓜染色体数为44,二倍体西瓜染色体数为22,由于染色体数目不同,精细胞和卵细胞结合时具有一定的不亲和性,这就给无籽西瓜的“制种”带来一定的困难,表现为结实率大大下降,而发芽率又不高。由于产 Seedless watermelon breeding, nearly 50 years of history, is the use of tetraploid watermelon and diploid watermelon hybrid seed, grow into a seed, watermelon is seedless, because two different watermelon chromosome number, fine Egg-binding can not be paired, just as horses and donkeys have mules, and mules can not bear the same. Because tetraploid watermelon chromosome number 44, diploid watermelon chromosome number 22, due to the different number of chromosomes, sperm cells and egg cells have a certain degree of non-affinity, which gives seedless watermelon “seed” with To a certain degree of difficulty, manifested as a substantial decline in seed set, and germination rate is not high. Due to production