Studying Virulence Of Yam Anthracnose Fungus From South And Evaluation Of Anti-anthrax In Yam Germplasm

Yam is an important yam crops, having a lot of planting in southern China and northern China. Yam Anthrax is the most serious disease in producting of yam, widely occuring in the planting area, has seriously affected the yam production. Currently, there is a lack of research and study on China’s southern region of Yam Anthracnose pathogen systems. In this study, collected the southern region of Yam Anthracnose fungus and measured its virulence, resistance to Anthracnose of Yam Germplasm screening, and a preliminary study the mechanism of Yam Germplasm resistant to Anthracnose. Experimental results were as follows:1、Isolating from Yam diseased samples collected from Si-chuan, Chong-qing, Yun-nan, Gui-zhou, Hu-nan, Guang-xi, Fu-jian and Hai-nan eight provinces, the all about of103pathogens.Using EP pipe slope and filter paper are two ways to save the pathogens. After morphological and ITS sequence analysis identified a total of45copies of Yam Anthrax strains, and all of them are Colletotrichum gloeosporioides, where39of C. gloeosporioides vegetative state, six of sexual state.2、Using detached leaves inoculated with virulent strains detected, the experimental results show that45parts obtained from different sources in the presence of virulent strains of Yam Anthrax differentiation phenomenon, six Yam Anthraxs stronger performance from the Guang-xi region pathogenicity; and the average of disease index was40.76-63.15; seven weakly pathogenic Yam Anthraxs from Si-chuan and Yun-nan Anthrax performance, with an average disease index was19.71-19.88; other regions about32parts Yam pathogenic Anthrax performance, with an average disease index was31.83-40.46.3、Using the virulent strains103of Yam Germplasm resistance experiments were conducted to screen Germplasm resistant to Anthracnose, the experimental results showed that:the19parts germplasm highly resistant germplasms, all of them are wild resources; midanti-Germplasms of25copies are from farm species;21Yam Germplasms copies are in a sense species, both the38Yam Germplasms copies from farm species all of then are high sense species.4、By a preliminary study on the different levels of resistance to Yam Germplasm resistance physiological and biochemical indexes, the results showed that:wild Yam Germplasm stomatal density, content of phenolic compounds wax content and peroxidase activity were higher than the farm Yam Germplasm species, reached a significant level; stomatal density, content of phenolic compounds, wax content and peroxidase activity changes with Yam Germplasm resistance has a significant correlation was significantly positively correlated. Stomatal density volume, phenolics content, wax content and peroxidase activity and resistance to change was also significantly correlated0.926,0.865,0.844and0.766, respectively. Thus, these indicators of resistance have an important role in disease resistance in Yam Germplasm. And phenylalanine ammonia lyase activity changes both in Yam Germplasm resistant or susceptible yam germplasm has no rules to follow, the reason for further research to explore.