马铃薯纺锤块茎类病毒不同株系及不同接种方法对产量的影响

马铃薯纺锤块径类病毒(Potato spindle tuber viroid)是危害黑龙江省马铃薯生产的一种重要病害。为了查明不同类病毒变株对主栽品种克新1号和4号所引起的产量损失和症状反应,应用往复聚丙烯胺凝胶电泳法(Peturn-Polyacmdegel electophoresis)鉴定类病毒。试验结果表明,接种当年,接种类病毒的处理平均减产37%,按商品产量计算减产达47%。当年表现症状的植株平均为59.6%,块茎产生症状的植株平均为57.4%。用于接种的3个马铃薯纺锤块茎类病毒变株的致病力,以当地的类病毒弱系为最强,其次为北美的类病毒强系,北美的类病毒弱系的致病力较弱。类病毒对产量的影响与马铃薯品种和类病毒变株的组合有极为密切的关系。克新1号接种当地的类病毒弱系时薯块严重畸变,商品产量只为不接种对照的21%。用往复电泳法检测各个试验处理被类病毒侵柴的情况,芽接种处理,于出苗后1周即可检测到类病毒,叶接种处理,于接种后2周即能检测到类病毒。出苗后7周,植株中类病毒浓度达到高峰,随即急剧下降,到出苗后10周,大部分接种植株已检测不到类病毒。块茎直径达1厘米时,即能检测到类病毒,随着块茎膨大,类病毒浓度也相应增高,到收获前,块茎中的类病毒含量只略低于植株含类病毒高峰期的浓度。用于本试验的克新1号、4号无类病毒和主要马铃薯病毒的核心材料,在1988年已交付给省内外的良种场繁殖使用。于当年秋季抽样检测克山第二良种场连续种植二年的种薯,当年种植试管苗生产的种薯,以及试管苗等,均未检测到类病毒。

INFLUENCE OF VARIOUS METHODS OF INOCULATION AND VARIOUS STRAINS ON THE INFECTION OF POTATO TPINDLE TUBER VIROID(PSTV)AND ITS YIELD LOSSES

The purpose this study was to detemine the influence of strains of potato spindle tuber viroid and of several inoculation ways on the infection of plants, detectability, and its yield losses by mechanical inoculation oi sprouts, leaves and both sprouts and leaves in screenhous experiments.Three potato cultivars(superelite) were used for study: Kennebec, Kexin No. 1 and Kexin No. 4 Strains of PSTV: severe, mild originated from North America and another mild strain isolated from a local cultivar were used for inoculation.The highest ifection rate of potato plants with PSTV, highest percentage of plants with disease symptoms on plants and tubers and highest yield losses were obtained after both sprouts and leaves inoculation, followed by sprouts, and leaves inoculation.The highest yield losses were acquired by inoculation with a locally mild strain of PSTV, followed by inoculation with severe strain and mild strain originated from North America respectively. The development of symptoms and yield losses is also affected by PSTV strains. The locally mild strain of PSTV inoculated produced more severe symptoms of PSTV and yield losses than the severe and mild strains.The most intensity of PSTV symptoms and yield losses results from com- bination between PSTV strains and potato cultivars.When Kexin No. 1 was inoculated with locally mild strain of PSTV, it developed most severe symptoms of PSTV and produced less marketable yield, it was as little as 23% of the uninoculated control. The. relative concentration of PSTV during current year of infection was evaluated by Return-polyacrylamide gel electriphoresis. The PSTV was detected as early as 1 week after emergence in samples taken from middle leaves of sprouts inoculation methods and early as 2 weeks after inoculation in leaves taken from leaves inoculation methods. Thereafter the PSTV concentration inereased rapidly in middle leaves and reached a peak 7 weeks after emergence lor sprouts inoculation methods, and 6 weeks after inoculation for leaves inoculation methods, and then declined sharply. 10 weeks after emergence, the PSTV concentration in middle leaves reched a lowest level sometimes in was not detected by R-PAGE. The PSTV was readily detected by R-PAGE after tuber initiation. While the tubers are increasing with weighes, the concentration of PSTV in tubers was rised, and reached a highest level, when potato plants came to maturity.The nucleic propagating materials free from viroid were planted two year by a elite seed farm, some tubers of the nucleic propagating materials were sampled and detected viroid by R PAGE this year. The potato spindle tuber viroid was not detected in these samples.