烟草不同生育阶段对黄瓜花叶病毒侵染的表现

为了探索烟草不同生育阶段对CMV的侵染反应、为防治烟草黄瓜花叶病提供理论依据。1984～1986年对不同生育阶段的烟草品种“Speight G28”、“Nc89”、“中烟15”以CMV接种。观察其侵染和发病情况及对各个器官和产量的影响、试验结果指出:3个品种从大十字期至现蕾期对CMV的侵染无抵抗能力,但各生育阶段的耐病性存在明显差异。SpeightG28,中烟15自大十字期至50天属于感病阶段、50天后属于耐病阶段。“Nc89”前40天属于感病阶段。在感病阶段中、前两个品种又有两个高峰期、分别为从大十字期至第10天和第40天左右、“Nc89”为第10天和第40天。第一次高峰尤为严重、病情指数可达80以上、产量降低35%左右、潜育期短13～15天、推迟现蕾期30～50天、个别植株不能现蕾。耐病阶段病情指数低于40以下,产量降低10%左右。植株的感、耐现象与体内的蛋白质、总糖的含量有密切的关系。

REACTION OF RESISTANCE TO CUCUMBER MOSAIC VIRUS AT DIFFERENT GROWTH STAGES OF TOBACCO

Three varieties: Speight G28, NC89, and China Tobacco-15 were inoculated at differ- ent stages with cucumber mosaic virus (CMV) from 1984 to 1986. The results indicated that the ability of these varieties to tolerate CMV infection varied considerably from seed- ling to squaring phases. From the first inoculation in the 4 true leaf phase up until the fiftith day, the tobacco plants showed no tolerance To CMV. There were two highly sus- ceptible days of the growth phase: the tenth and the fortieth. The tenth day proved to be the most suscepible with the shortest incubation period, highest disease index (87.5), great- est reduced total output (40.33.%), and longest postponement of the squaring period (approx. 45 days). The mechanism of susceptibility to CMV was inversely proportional and proportional to the amount of sugar and protein, respectively. It is evident that the 6-7 true leaf phase of the seedling period is significant with respect to control of CMV.