Evaluation Of Resistance To Disease Caused By Alternaria Alternata Or Ascochyta Onobrychidis Among Sainfoin Varieties

Sainfoin(Onobrychis viciaefolia),as an important forage legume plays an important role in grassland livestock production and environmental protection world wide.Disease is one of the main limiting factors of sainfoin production and utilization.Breeding and utilization of disease resistant varieties is the most efficient way to control disease of sainfoin. However,available information is scare on the evaluation of sainfoin disease resistance..In this study,seven sainfoin varieties were planted in pot and inoculated with Alternataria alternate or Ascochyta onobrychidis in greenhouse.The diseases resistances were assessed base on the biomass and physiological indexes,The main results were summarized as the follows:1.Biomass:The inoculation of the two fungi decreased the biomass of all tested sainfoin varieties.The decreasing range were 3.92%-76.67%to A.alternate and 8.97%-76.78% to A.onobrychidis,of which varieties of Eski and Gansu given the lowest and the highest biomass lose to the inoculation of the two fungi.2.Photosynthetic rate:The inoculation of the two fungi decreased the photosynthetic rate of sainfoins,the decreasing ranges of the photosynthetic efficiency by A.alternate and A.onobrychidis were between 34.23%-69.77%and 14.8%-47.89%,respectively.Eski had the lowest photosynthetic efficiency decreasing by the two fungi.The inoculation of A. alternate decreased the Melrose photosynthetic efficiency by 69.77%,while the inoculation of A.onobrychidis decreased Gansu photosynthetic efficiency by 47.89%.3.Protein:Protein content of all sainfoin varieties were decreased by inoculation of the two fungi.Protein content of plants inoculated with A.alternate and A.onobrychidis were only 50.37%-82.06%and 57.42%-77.28%to control at the eighth day after inoculating. Eski always has the highest protein content among the 7 varieties during the experiment.4.Chlorophyll:Chlorophyll content reduced day by day after inoculated with A. alternate and A.onobrychidis.Chlorophyll content was only as much as 44.70%-72.10% compared with control at the eighth day after inoculation,of which Don and Mongolian had the lowest chlorophyll content.Eski had the highest chlorophyll content in all varieties during the experiment, 5.Other physiological indexes:Soluble sugar and proline concent in the 7 sainfoin were also decreased by the inoculation of A.alternate or A.onobrychidis.Eski had higher soluble sugar and proline content than other varieties,the content were 80.47%and 85.92%,respectively,when inoculated with A.alternate,and 99.36%and 94.71%, respectively when inoculated with A.onobrychidis,Malondialdehyde(MDA) concentration of the 7 varieties changes everyday after inoculated with the fungi,the maximum and the minimum values appeared on the first and forth day,respectively,after inoculation..There were no significant difference of MDA concent of the 7 varieties expect Eski had significantly lower MDA content.POD and CAT activities of sainfoin increased at the beginning and then declined later, the maximum value appeared on the second day after inoculation Compared with control, POD and CAT activities of the 7 varieties were 75.46%-95.51%and 79.87%-96.56%, respectively,when inoculated with A.alternate,at the eighth day and 93.07%-102.43% and 85.24%-101.11%,respectively,when inoculated with A.onobrychidis at the eighth day.Based on the results mentioned above,we concluded that:the inoculation of A. alternate and A.onobrychidis decreased,in various extent,the biomass,photosynthetic efficiency,protein content and other physiology indexes of all varieties tested in the experiments,and the varieties had different resistant to these two fungi.Eski had better performance than other varieties in all parameters examined,it has higher resistant to the two fungi.