The Resistance Identification Of Tomato Powder Mildew Seedling And Selection Of Resistance Resources

Tomato powdery mildew was a fungal disease, which extensive happened in China and world. It happened to land and greenhouse. The disease mainly happened in leaf, occasionally in pedicle and fructification. With tomato was planting largely in our country, tomato powdery mildew became increasingly serious. We must find an effective method to solve this problem. Disease resistant breeding is the most basic way to deal with such problem. The study began with the deniycation of the pathogenic bacteria and the biological characteristics of the pathogenic bacteria were initially studied. Secondly the purification and store method of pathogenic bacteria were researched. Then the physiological biochemical character of tomato powdery mildew was studied, including growth temperature, light, pH and humidity of most suitable for pathogenic bacteria. The method of inoculate powdery mildew in optimum tomato seedling stage was determined by L9(33) Orthogonal design, with this method, germ plasma resources of resistance to tomato powdery mildew in54breeds which were from the Tomato Breeding Institute of Horticulture College in Northeast Agricultural University were filtered. The results were as follows:First, Erysiphe polygoni DC is the pathogenic bacteria of tomato powdery mildew at the greenhouse of Xiangfang farm in Northeast Agricultural University. It belong to Eumycetes Ascomycotina, Pyrenomycetes, Erysiphales, Erysiphaceae, Erysiphe.Second, three methods of store the pathogenic bacteria of tomato powdery mildew were researched. The time of vital preservation is the longest for80days; leaves butterfly save method for40days in the next, the preservation of leaf in vitro is shortest for25days.Third, the experiment found that the optimum growth temperature of tomato powdery mildew is20℃. The pathogenic bacteria of tomato powdery mildew grew best in the dark. Spore germination of pathogenic bacteria decreased as the ultraviolet irradiation time lasting. When irradiation time reached60minutes, spore all dead. The suitable humidity for conidiophores to germinate was100(RH=100). When pH at8, the germination of conidiophores was best and the activity was most vigorous.Forth, this study suggested the optimal combination was inoculation at four leafage with106spore per milliliter inoculation concentration by spraying inoculation method, which filtered by the identification method of tomato resistance to powdery mildew at seedling stage.Finally,54varieties of tomato seedlings which offered by the Tomato Breeding Institute of Horticulture College in Northeast Agricultural University include4resistant materials,16medial-resistant materials,17susceptible materials and17extremely susceptible materials.