Protocol Establishment For Evaluation Of Resistance Of Garlic To White Rot (Sclerotium Cepivorum Berk.) And Identification Of Garlic Germplasm Resistance To White Rot

Garlic white rot, a destructive disease of garlic, mainly damage the roots, bulb, and leaves of garlic. It may cause death of young plants and influence garlic production in fields, with great subsequent loss in yields or even no harvest during severe incidence, medicine prevention has disadvantages due to existing drug residual, therefore, it is important significance to select and breed fine garlic cultivars which are resistant to garlic white rot and also have high yield. The research focuses on the resistance identification method, the germplasm resources resistance to garlic white rot, which provides reference for the garlic germplasm evaluation, breeding and the varietal selection in the cultivation.A resistant garlic cultivar Hanzhong Red Skin (R) and a susceptible cultivar Gailiang (S) were employed to establish a protocol involved in evaluation of resistance of garlic to white rot(Sclerotium cepivorum Berk.). Results showed that at seedling stage the pathogen was able to infect garlic plants through both the wound and the natural orifices, while at flower bud differentiation stage it invaded the plants mainly through the wound. The plants with 3-week-leaf age,4-week-leaf age,5-week-leaf age,6-week-leaf age were choosen for inoculation. The result showed 6-week-leaf age was recognized as the best time for inoculation. In vitro inoculation was much simple and efficient, compared with in vivo inoculation. There was no significant difference in disease evaluation between leaf face inoculation and leaf back inoculation. We set up four incubation temperature, respectively 16℃,18℃,20℃,22℃. The research showed the optimal incubation temperature was 18℃, we observed disease-resistant evaluation after inoculation from the fourth day, the optimal time for disease-resistant evaluation after inoculation was 7-8 days.Protocol establishment for evaluation of resistance of garlic to white rot was leaf face inoculation,6-week-leaf age inoculation, incubation temperature was 18℃, the disease-resistant evaluation after inoculation was 7-8 days.The procedure developed from the present study was further applied to evaluate the resistant ability of other three garlic genotypes to white rot. Results obtained demonstrated that the established method was applicable to a wide range of garlic genotypes for testing their resistance to white rot.Forty-four garlic cultivars were identified and evaluated by the method which had been established. There is no one which is immune to the garlic white rot amongst the tested cultivars. G007, G020, G094, G095, G104, G109, et al,6 cultivars are highly-resistance; G005, G008, G009, G022, G026, G075, G096, G098, G092, G100, G103, G107, et al,12 cultivars are resistant; G003, G004, G015, G018, G024, G025, G029, G039, G057, G059, G073, G084, G085, G087, G089, G090, G091, G097, G099, G102, G105, G110, et al,22 cultivars are sensitive. The 4 highly-susceptible cultivars are G001, G074, G101, G106.