长期以来西瓜品种更迭缓慢,良种繁育工作没有跟上,品种混杂退化;另一方面,西瓜生产受气候条件的影响,产量低,且很不稳定。西瓜的商品率低,具有品种典型性的果实比例不高,瓜形大小不一,果皮色泽各异。果肉含糖量降低(一般固形物含量只有7～8%),种子数量增加,果皮增厚,食用比例降低。田间表现为抗病性下降,座果率降 For a long time, the varieties of watermelon changed slowly, the breeding of breeding seeds did not keep up, and the varieties mixed and degenerated. On the other hand, the production of watermelon was affected by climatic conditions, with low yield and instability. The product rate of watermelon is low, with the proportion of typical varieties of fruit is not high, melon-shaped size, peel color varies. Pulp sugar content decreased (the general solid content of only 7 to 8%), increased the number of seeds, peel thickened, reduced the proportion of food. Field performance decreased resistance, fruit set down rate