Resistance Identification Of Different Melons To Acidovorax Citrulli And Studies On Morph-physiology Of Disease Resistance

The 25 different sources of melon materials were used for the subjects, identification of melon materials resistance by the method of seeding spray inoculation at grows to 2-3 true leaves with Acidovorax citrulli in glasshouse. Identified of melon materials resistance by the method of in vitro spray inoculation in young fruit stage and developing fruit stage in glasshouse. At the time, according to the results of resistance identification were screened determinated the physiologic index, determinated the different resistant materials leafs with soluble protein, total sugar, free amino acid, total phenol, flavonoids, chlorophyll content and water content. Finally, observed the morphological structure of resistant and susceptible materials of fluff, stomata by the microscopy and electron microscopy technology, observed the skin structure of fruit in different times. And the main results were as follows:(1)Identified the resistance of 25 different of melon materials by the method of spray inoculation at seedling stage.The results showed that screened the 8 middle resistant varieties included T1,T4,T11,etc.The 8 middle sensitive varieties and 9 high sensitive varieties included T6,T12,T13, etc. No immune and high resistant materials. In addition, the redults of resistance to investigation showed that field of plant disease symptoms materials T12, T13, T20 sum to 5 materials were all belong to the level of high or middle sensitive.The rest of 20 melon materials have no symptoms.(2)Identified the different of melon materials by the method of in vitro spray inoculation in young stage and developing stage. The results showed that 11 copies were middle resistant materials,5 copies were middle susceptible materials and 9 copies were susceptible materials. The top three comprehensive resistance indexes of the materials were T4,T10 and T6 achieves 0.7 above. The lowest comprehensive resistance indexss of the materials were T2, T23 and T24. The resistance index of the 5 copies materials included T6 and T9 in the young stage of fruit were significantly higher than developing stage. The resistance index of 7 copies materials included T3 and T8 in the developing stage were significantly higher than the young stage.(3)Comprehensived 25 different muskmelon seedling stages and two different stages of fruit with resistance index to Acidovorax citrulli.The results showed that most materials seedlings and fruits resistant performance were not consistent. Some of materials has obvious differences to Acidovorax citrulli in the fruit growth in different stages.The highest comprehensive resistance materials were T4 and T10, T4 material fleshy soft, crisp and delicious, could give priority to as the material of disease resistance breeding.(4)Through determined the related physiological indexes of different resistant materials leaves. The results showed that although water content, soluble protein, total sugar, free amino acid content were significant difference, but the resistance materials between susceptible materials have no regularity. And relative chlorophyll content, total phenol and flavonoids content were connected with resistance of materials. The chlorophyll content of resistant materials living plant in leaves was higher than susceptible materials.The total phenol and flavonoids content of resistance materials in the leaves were generally lower than susceptible materials.(5)Observed the fluff and stomata tissue morphology structure in leaves of the resistant and susceptible materials by microscopic and electron microscopic technology. The results showed that resistant materials leaves were generally thickness than susceptible materials and have significant difference. By comparing the observation of 2 different resistance materials found that the leaves thickness were also extremely significant difference. By comparing the fruit skin structure preliminary found that the lenticels numbers of fruit skin surface of resistant materials T4 more than susceptible materials T20. But the fruit skin structures have no difference. By comparing the fruit skin structure in early stage found that the outer epidermis cells of susceptible materials arranged loosely,the outer epidermis cells of resistant materials arranged closely and orderly.The thicknesses of cortex fruit appearance of resistant materials were thicker than susceptible materials.