玉米不同生育期接种玉米矮花叶病毒后对种子带毒率和寄主抗性水平的影响

在严格防虫网室和温室内，分别在抗、感、耐3个玉米自交系的苗期、拔节期、大喇叭口期和抽雄孕稳期接种玉米矮花叶病毒（MDMV），测定所结种子的带毒率。结果表明，3个自交系对MDMV接种感染后的种子带毒率有明显差异，黄野四-3（R），7922（S）和81515（T）的平均种子带毒率依次为0，1.65％和0。从苗期到抽雄孕穗期，其中7922病株率分别为100％，100％，63.6％和10.1％;病情指数分别为95.6，82.4，63.6，11.1;种子带毒率分别为2.3％，15％，3.3％和0.78％。不同生育期接种MDMV对玉米的抗病性影响为玉米苗龄越小，抗病毒能力越弱，反之越强。

A Preliminary Study on Effects of Seed-borne Virus Rate and Resistance Level by Inoculating MDMV in Different Growth Periods

In insect-proof greenhouse, 3 corn inbred lines-Huangye 4 - 3 (R), 7922 (S) and 81515(T) were inoculated with maize dwarf mosaic virus (MDMV). The inoculated periods were designed to differ from 3 - 5, 6 - 8, 9 - 11 to 13 - 15 leaf stages and the rate of seed-borne MDMV was detected by bioassay. The results showed that (1 ) the rates of seed-borne MDMV were in Huangye 4 - 3, 7922 and 81515; 0%, 1. 65% and 0% in Huangye 4 - 3, 7922 and 81515 respectively, (2) and inbred 7922 from seedling stage to booting stage, MDMV infection rates were 100%, 100%, 63. 6% and 10. 1 %, disease indexes were 95. 6, 82. 4, 63. 6,and 11. 1; seed-borne MDMV rates were 2. 3 %, 1. 5 %, 3. 3 %, and 0. 78 %. The resistance evaluation to the 3 inbred lines indicated that resistance levels were related to infected plant growth periods. The younger plants they were, the lower resistance they showed to MIMV infection.