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Acta Prataculturae Sinica ›› 2022, Vol. 31 ›› Issue (2): 133-146.DOI: 10.11686/cyxb2020519

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Disease resistance evaluation of 32 alfalfa varieties in Xinjiang

Yue-yang ZHANG1(), Fang LI1, Wei-wei LIANG2, Yan-zhong LI1()   

  1. 1.Engineering Research Center of Grassland Industry,Ministry of Education,Key Laboratory of Grassland Livestock Industry Innovation,Ministry of Agriculture and Rural Affairs,Gansu Technology Innovation Center of Western China Grassland Industry,National Demonstration Center for Experimental Grassland Science Education,State Key Laboratory of Grassland Agro-ecosystems,College of Pastoral Agriculture Science and Technology,Lanzhou University,Lanzhou 730020,China
    2.Grassland Institute,Xinjiang Academy of Animal Sciences,Urumchi 830000,China
  • Received:2020-11-25 Revised:2021-01-18 Online:2022-02-20 Published:2021-12-22
  • Contact: Yan-zhong LI

Abstract:

This research aimed to identify disease resistant, high-yielding alfalfa (Medicago sativa) varieties suitable for planting in Xinjiang and was conducted in Hutubi, Changji City, Xinjiang in 2018 and 2019. Disease incidence and disease indexes were scored on two dates in both years for 32 alfalfa varieties. In total, yield data for 5 cuts were collected and plant survival percentage was measured in 2019. Diseases observed included: Phoma leaf spot and black stem, powdery mildew, alfalfa yellow leaf blotch, Stemphylium leaf spot and Cercospora leaf spot. Among these, the most important were powdery mildew, Phoma leaf spot and black stem, and alfalfa yellow leaf blotch, with the highest incidence of these three diseases being 97.08%, 100.00% and 57.14%, respectively. The resistance of each variety to each disease was evaluated following standardized scoring systems, and “gray incidence degree analysis” was used to analyze the characteristics of each variety and provide a combined trait score based on disease resistance, yield and survival. The 32 tested varieties were categorized as having “high resistance” (HR), “resistance” (R), “medium resistance” (MR), “low resistance” (LR), or as “susceptible” (S) to each of the three main diseases. Among the 32 tested alfalfa varieties, for resistance to Phoma leaf spot and black stem, the numbers of varieties in each of these 5 categories were: 17 HR, 8 R, 4 MR, 1 LR and 2 S. For alfalfa powdery mildew, the numbers of varieties in each category were: 0 HR, 1 R, 8 MR, 5 LR and 18 S. For alfalfa yellow leaf blotch, there 29 HR varieties, 3 R varieties and no MR, LR, or S varieties. The total yields over two seasons for the different varieties ranged from 22.48 t·ha-1 for “Longdong” to 29.52 t·ha-1 for “Longwei 3010”. No freezing injury occurred in any of the tested varieties; all survived well. Plant survival was greater than 80% for all varieties and was above 90% for 22 varieties. The five varieties with the highest combined trait scores from gray analysis were “Phabulous” (score 0.942), “WL363HQ” (0.897), “Zhongmu No.3” (0.877), “Aohan” (0.853) and “Dryland” (0.850), while the five lowest-scoring varieties were Salt-tolerant Star (score 0.650), WL343HQ (0.679), Shockwave (0.699), Instict (0.718) and Longdong (0.721).

Key words: Medicago sativa, disease resistance, gray incidence degree analysis