Resistance Identification And Mechanism Of Biochemistry Of Alfalfa To Common Leaf Spot

In this paper, methods of five alfalfa cultivars seedling inoculation to common leaf spot were studied. Meantime, resistance evaluation of 60 materials were conducted after inoculation with Pseudopeziza medicaginis to screen the best resistant ones to common leaf spot. Changes of 3 enzyme's activities and their relationship with alfalfa's disease resistance were also studied to preliminarily clarify physiological and biochemical mechanism of alfalfa to common leaf spot. The results were as following:1. Researches on inoculation methodsSowing fungus plants and spore spraying are two ideal plant inoculation methods which can screen resistant alfalfa varieties and plants quickly and accurately.2. Identification and screening of 60 materialsThrough identification and screening of 60 materials, results indicated that there are significant differences between materials of same varieties, which means the foregoing work was successful, and it also proved that disease resistance can be well reserved and transmitted with this process of resistance identification, screening and single harvest. Correlation between alfalfa's biological traits and disease index were analyzed, the results showed: leaf width of alfalfa was middle negatively correlated to disease index, and other biological characteristics were low-correlated. As a result, biological traits didn't directly correlate to disease index; there are some possibilities that alfalfa's disadvantageous living condition influenced the expression of alfalfa's disease resistance. Results of resistance identification indicated, Saranac susceptible, Shahe susceptible, Shawan susceptible and Jingyang susceptible were high-susceptible materials; Iroquois susceptible and 38 susceptible were middle-susceptible materials; Jingyang resistant, 38 resistant and Shawan resistant were middle-resistant materials; Iroquois resistant, Saranac resistant and Shahe resistant were high-resistant materials. These results provided the foundation of materials combination for hybridization breeding project of next step.3. Studies on relationship between 3 enzyme's activities and material's disease...