Abstract: Odontothrips loti Haliday is one of the most important pests which affect hay yield and quality of alfalfa seriously in north China.At present,controlling methods on this pest is pesticide spraying.However,it has hardly any ideal effect using single controlling method because of the short growth period,miniature body,easy enshrouded,and anti-pesticide of the thrips.Using varieties resistant to insect is one of the most effective approaches to solve thrips damage on alfalfa ultimately.In this study,the tolerances of 8 alfalfa varieties to O.loti were evaluated at alfalfa 6-leaf-stage by infecting 3,5 and 10 adult thrips per plant,respectively.The results indicate,after 5 day feeding by thrips,the damage indices of all alfalfa varieties were increased significantly and the plants from some varieties were dead along with the increased thrips density.M8 and HA-3 alfalfa were the resistant varieties to O.loti in this study,Ja alfalfa was susceptible,and other varieties were medium.Accordingly,the yield loss ratios of HA-3 and M8 were the lowest, Ja alfalfa the highest,and other varieties medium;same situations as the plant height and branching.In summary,the tolerance of Ja alfalfa to O.loti was the poorest,while HA-3 and M8 were the best.

Key words: Alfalfa variety, Odontothrips loti Haliday, Yield loss ratio, Height, Branch

摘要： 评价8个苜蓿品种在牛角花齿蓟马(Odontothrips loti Haliday)不同密度成虫为害后的抗性表现,并从株高、分枝数及产量损失率3个方面测定,以揭示各品种对蓟马的耐害性以及苜蓿抗蓟马研究的最适接虫量.结果表明:随着虫口密度的增大,各苜蓿品种植株的为害指数明显上升,M8和HA-3苜蓿均表现为抗牛角花齿蓟马,Ja苜蓿表现为高感蓟马,其他苜蓿品种处于中等水平;产量损失率M8、HA-3最低,Ja最高,在株高和分枝方面呈现相同规律;研究表明M8、HA-3苜蓿对牛角花齿蓟马的耐害性最高,Ja苜蓿的耐害性最差.

关键词: 苜蓿品种, 牛角花齿蓟马, 产量损失率, 株高, 分枝