[Characteristics of germplasm resources in Coix from xishuangbanna].

OBJECTIVE: To evaluate the genetic diversity among wild germplasm resources of Coix that distributed at altitude of 550-1550 m in Xishuangbanna, Yunnan province by comparing the morphological variation, biological and economical factors. METHOD: The field plot experiments were conducted to observation the germination rate, growth period. While the milled rice rate, content of protein, crude fat and ethanol extract of 9 wild Coix germplasm resources were measured. RESULT: The germination rate of 9 germplasm was from 22% to 81%, and the growth period was among 139-156 d, which belongs to the medium-late mature type. The germination rate, growth stage, plant height, leaf length and width, tiller number, ramification number, seed number per stem of 9 Coix germplasm were significantly different (P < 0.05), respectively. The range of seed total protein contents were from 15.63% 25.74%, crude fat contents were from 5.05%-7.14%, and the contents of alcohol extract, which showed antitumor activity, were from 5.85%-7.27%. CONCLUSION: The fact of quite different in plant morphological, biological and quality characters of 9 germplasm suggested that the genetic diversity in the wild populations of Coix distributed throughout the regions of Xishuangbanna is relatively abundant.

[Identification of disease resistance to Ustilago coicis in southern Coix germplasm].

OBJECTIVE: To identified the resistance of Coix to Ustilago coicis and screen the high disease-resistance Coix germplasm. METHOD: 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. RESULT: 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. CONCLUSION: 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.