The fruits of watermelon are often found cracking duiring the whole Fruit development. Fruit-cracking results in lower yield and quality, easier infection to the deseases and more difficulties for sales. So it is a great significance to study mechanism of fruit-cracking in watermelon. However, fruit-cracking indicators and evaluation criteria have not yet established, and some good crack resistance merterials have not been well used. Therefore, a group of tests, such as morphology, physical and chemical mec...