Studied On Alfalfa Varieties Resistance And Induced Resistance To Fusarium

1. 30 alfalfa varities were evaluated resistence for F.solani. F.semitectum and F. camptoceras with seedling rot.The rwsults showed the endurce resistant varieties including Muxuwang,Delilande,Xinjiangdaye and Jinghuanghou, the disease index from 29.17～36.87, the frequency of 13.33 %;That sensitive varieties with the index from40.30 to59.38 ,the frequency of 76.67 %;Qingyang,Debao and 74-27 are three high sensitive varieties with the index 74.31,71.11 and 66.94, the frequency of 10%.There was no resistance and immune varieties.2. The effect of 5 elicitors on the growth of mycelium and gerimination of macrospores of Fusarium were studied. The results showed that there was nei inhibition nor stimictation.Elicitors seedling spraying for SIR was tested. The results showed that all of these 5 elicitors could get induced the resistance to crown and root rot of alfalfa, but the effects were different.The effect of chitosan was the best one, which the induction and disease index could reach 37.22% and 39.8 when was sprayed with 0.5 ug/mL chitosan.Evaluated the SIR inoculation pathogens. The results showed that 0.5 ug/mL chitosan-treatment had the best SIR to crown and root rot of alfalfa. Resistance inducted resistence was obtained after chitosan treatment 5 days. The incidence of disease reduce and disease index is 42.8. And the effect reduced gradually and it could last about 15 days and provided 24.6%control.Systemic induced resistance was obtained spraying leaves with chitosan . The result showed testing root could get systemic induced resistance.3. The activity of PAL,POD,CAT,SOD,β-1,3-glucanase was tested . The results showed that all of the activity was increase after induction of 0.5 ug/mL chitosan.