Study On Germplasm Resource Exploitage And Bear-storage Mechanism In Edible Seed Watermelon

The edible seed watermelon germplasm resources and different types watermelon were used as materisls to research the genetic diversity of the edible seed watermelon, fruit bear-storage mechanism of the black-seed edible seed watermelon and breeding for seed or flesh with the germplasm resources.The results were as following:1 34 cultivars or strains incloud 4 edible seed watermelons, 2 wild watermelons and the different ecology type flesh watermelons were used to the research on the characters observation of plant growth period, the seed size and the fruit,RAPD mark,and cluster analysis. The results show that the seed size, weight of 1000 seeds, fruit development period and soluble solid content etc.of Jingyuandaban had obvious differences with flesh watermelons,most of them were extreme type, but the specially displays had not observe in other characters .The other 3 cultivars of edible seed watermelon, Neimengbaiguazi, Ninghong and Xinhong also had the certain difference with the flesh watermelon but range of difference was smaller; The RAPD mark and cluster analysis demonstrationed that 157 DNA bands amplfied with 16 random primers were observed and 67 of them were polymorphic.An average proportion of polymorphic loci was 42.68%. 34 cultivars or strains were classified into two sub-groups, which were cultivars and wild types, two wild types had the certain difference eath other, the genetics distance of most cultivars was smaller and had not related with the ecology types. From above indicated that the genetics background of cultivars of watermelon was quite narrow;The Jingyuandaban was far relation with the flesh watermelons, but its difference was not enough to divided another new variation.2 The edible seed watermelon'Jingyuandaban', comparing with flesh watermelon'Xinong-8'were used to research fruit bear-storage mechanism.The result shows:During early storage, the furit firmness of edible seed watermelon was relatively high, changing trend of propectin content was going up before 25 days,then droping gently,soluble pectin content gradually rised,and had kept high level in later storage; The furit firmness , propectin content of watermelon was lower than of edible seed watermelon, the difference of them gradually raised,and soluble pectin content was high.Pectinmethy lesterase (PE) and polygalacturonase(PG) activity of edible seed watermelon gently risen or comed down in storage; Variation range of PE and PG activity of watermelon were bigger,its rose to height ,then comed down quickly in storage.Ultrastructure of in middle fruit skin and flesh of edible seed watermelon and watermelon showed that cell wall,cell membrane et al were decomposed, middle lamella and micro-fibril were resolved in later storage.Its of them in watermelon were more seriously and early than in edible seed watermelon,and in the end of storage, cell original structure of watermelon was destroyed , but the structure of edible seed watermelon was much better.In storage, SOD activity of edible seed watermelon had kept to rise,POD activity...