四个苜蓿品种无性系大田抗蓟马性能评价

本研究选用室内筛选的4个不同抗性级别的苜蓿品种（HA 3、Ta、M8和Ja）的无性系，以大田苜蓿地牛角花齿蓟马为虫源，任其自然受害，以喷药小区为对照，于现蕾期测定分析各品种无性系的受害指数、虫量、农艺性状和产量损失率，结果表明，7月和8月，4个苜蓿品种无性系的受害指数的排列顺序均为HA 3＜Ta＜M8＜Ja，HA 3与Ja之间受害指数存在显著差异（p<0.05）；受害指数与虫口密度之间无相关性；各无性系受害株的株高、茎粗、节间长、叶面积及干重均显著低于对照（p<0.05），但分枝数和节间数均显著高于对照（p<0.05），其中HA 3的各农艺性状表现均优于其他苜蓿品种，产量损失率也最低。苜蓿对蓟马的抗性主要表现为耐害性，其中HA 3的耐害性最强。

Field evaluation of 4 alfalfa cultivars(clones)for resistance to thrips

Field evaluation on resistance of 4 alfalfa cultivars to thrips was carried out in Lanzhou in 2008.Thrip population in the field was mainly composed of Odontothrips loti Haliday,accounting for over 95%.The spraying results showed that the order of damage indices of the cultivars from low to high is:HA-3,Ta,M8 and Ja.The damage index of HA-3,which is susceptible to thrips,was significantly different from Ja(p＜0.05),but correlation analysis showed that the damage index was not significantly related to thrips density.Plant height,stem diameter,length of intemodes,lear area,dry weight of the 4 alfalfa cultivars were significantly smaller than the CK(p＜0.05),but the number of branches and internodes were significantly larger than the CK(p＜0.05).The resistance might be generated by tolerance,and HA-3 was highly resistant to thrips.