Abstract:

The aim of this field study was to compare the resistance of 48 alfalfa （Medicago sativa） varieties from China and abroad to three different diseases： common leaf spot （Pseudopeziza medicaginis）， downy mildew （Peronospora aestivalis）， and root rot （Fusarium acuminatum）. The study was conducted at Yuzhong Campus， Lanzhou University. The disease incidence rate was used as an indicator of susceptibility， and the internationally accepted alfalfa disease resistance evaluation grading standard was applied to compare resistance among the 48 alfalfa varieties. The results of our analyses showed that， in terms of resistance to common leaf spot disease， UC-1465 was a highly resistant variety， UC-1887 was a resistant variety， Siriver and Trifecta were medium-resistance varieties， Avora， Hunter River and Saranac AR were low-resistance varieties， and the remaining 41 varieties were susceptible varieties. In terms of resistance to downy mildew and root rot， all 48 alfalfa varieties were highly resistant varieties. The results of subordinate function analysis showed that Vertus， Zhonglan No.1 and Xinmu No.1 were strongly resistant to common leaf spot， downy mildew， and root rot， indicating that they are highly resistant varieties； while UC-1887， UC-1465 and Saranac AR had lower resistance to the three diseases， indicating that they are susceptible varieties.

Key words: alfalfa, common leaf spot, downy mildew, root rot, resistance evaluation