Identification of disease resistance to Ustilago coicis in southern Coix germplasm

To identified the resistance of Coix to Ustilago coicis and screen the high disease-resistance Coix germplasm.Field and laboratory biochemical methods were used for the resistance identification. Ninteen germplasms collected from 7 provinces in southern of China such as Yunnan, Zhejiang, Fujian etc. were inoculated with chlamydospore of U. coicis, respectively. The incidence of a disease in field was investigated and the level of resistance was evaluated. The PAL activity dynamic changes in different level resistant germplasms were further determined.The result of field test showed 1 germplasm was immune, 1 germplasm was high resistance which incidence rate was under 20%, 6 germplasms were moderate resistance with the average incidence rates ranged within 20% - 40%, 11 of 19 germplasms that average incidence rates above 40% were identified as sensitive resistance. The value of PLA activity peak of resistant germplasm in seedling was significant higher and appeared earlier than that of the sensitive ones after inoculating.Most collected C. lacryma-jobi germplasms are sensitive to smut in our investigation; the PAL activity may play important role in Coix germplasm for resistance to smut and the biochemical method may be as an aiding method to resistance identification of Coix germplasm.