玉米品种抗矮花叶病的介体传播研究初报

以中玉4号为试验材料,以江苏南京、东台田间自然发生的玉米病株为接种毒源,分析了一种新的玉米矮花叶病抗病类型。汁液摩擦接种试验结果表明,2￣3叶龄期中玉4号和高感品种掖单13一致,发病率均为100%,随着叶龄的增大,中玉4号发病率显著下降。蚜虫传毒结果表明,当接种蚜量由5头增至30头时,掖单13的发病率从5%增至100%,而与此同时中玉4号的发病率为0%。自然和人工接种条件下,饲养在中玉4号和掖单13上玉米蚜的生活力基本一致。综上所述,幼苗期中玉4号对SCMV-MDB表现为高度感病,6叶龄期后具有较强的成株期抗性,对玉米蚜无抗生性,即中玉4号对玉米矮花叶病的抗性表现为抗介体传毒过程而非抗病原病毒本身。

The Preliminary Study on the Resistance of Maize Varieties to Vector-transmission of MDMV

The resistance of a new maize variety Zhongyu No.4 to maize dwarf mosaic disease had been studied with the diseased maize leaves as inoculums which occurred naturally in Nanjing city and Dongtai country, Jiangsu province, China. The proportion of infected Yedan13 and Zhongyu No.4 plants were all 100 percent by sap-inoculation on the 2 to 3 leaf stage, and that of Zhongyu No.4 decreased markedly as the leaf stage of inoculated plant advanced. The diseased rate on Yedan13 increased with the number of vectors per plant, as the number of aphid per plant added from 5 to 30, transmission rate was up from 5% to 100%. Meanwhile the diseased rate on Zhongyu No.4 was zero. The aphid productivity on Yedan13 and Zhongyu No.4 was approximately same on the nature or manual tests. These results indicated that Zhongyu No.4 was highly susceptible to SCMV-MDB the pathogenesis of maize dwarf mosaic disease in its 3-leaf stage and some maturity resistance to SCMV-MDB after 6 leaves ages. Its resistance to maize dwarf mosaic disease was not due to the resistance to SCMV-MDB but to the process of aphid-transmission.