Management of pine wilt disease in Korea through preventative silvicultural control

Pine wilt disease (PWD) represents a major threat to forest ecosystems worldwide. Although PWD is now better understood, effective control measures for this disease have still not been devised. Here, we report several years of field studies on preventative silvicultural control of PWD. Silvicultural control through preventative clear-cutting and the manual removal of logs was implemented between 2005 and 2009 in 16 Korean districts that had newly PWD-infected stands. Preventative clear-cutting of neighboring asymptomatic pine trees (within a 10-50-m radius of wilt trees) and the removal of felled logs or branches suppressed spread of PWD. Occurrences of PWD wilt pines in districts (city or county) subjected to this silvicultural control method were significantly reduced compared with those in districts using conventional controls (physical or chemical treatment of wilt pine trees). Through silvicultural control, PWD was successfully suppressed in 11 of 16 districts investigated. In contrast, successful control was achieved in only 1 among 18 districts subjected to conventional control. Our results will be of considerable interest to those engaged in the very difficult battle against the global spread of PWD.     

四种AM真菌接种剂的田间效应及其分子检测研究

采用灭菌土壤生产了 4种AM真菌接种剂。在盆栽条件下测试了接种剂的质量 ,结果显示 ,4种接种剂促进玉米生长效果明显 ,地上部分生物量均显著高于对照 (p <0 .0 1 ) ;以MPN试验检测了接种剂的侵染能力 ,结果表明每克接种剂中真菌的繁殖体数在 95～ 1 4 0 0之间。将AM真菌的预接种技术和农业生产上的营养钵育苗技术相结合 ,进行了玉米的田间试验 ,结果显示 ,玉米根系的AM真菌感染率早期增长较快 ,然后趋于平稳 ;AM真菌接种剂A(Glomusconstrictum)、C (Glomus三种菌混合 )和D (G .intraradices)对玉米籽粒产量有显著的增产效果 (p <0 .0 5 ) ;玉米籽粒的淀粉含量和磷含量也高于对照。运用特异性分子探针和nest ed PCR技术 ,从田间接种AM真菌Glomusintraradices和G .mosseae的玉米根样中粗提DNA进行特异性扩增 ,成功地从感染根段中检测到特定的接种AM真菌。本工作从分子水平为评价高效AM真菌的应用潜力、研究AM真菌之间及其与其他微生物之间的相互关系奠定了基础。     

Extent and Pattern of Genetic Diversity for Morpho-agronomic Traits in Ethiopian Highland Pulse Landraces: I. Field Pea (<Emphasis Type="Italic">Pisum sativum</Emphasis> L.)

An experiment was conducted in 2001 at Holetta and Kulumsa, Ethiopia, to study the extent and pattern of genetic diversity in Ethiopian field pea (Pisum sativum L.) landraces. One hundred forty-eight germplasm accessions were grown in an alpha lattice design with 2 replications. Data on 12 traits were collected and analyzed. Differences among the accessions were significant for most of the traits (except number of seeds/ pod) at each location even though differences pooled over location were mostly non-significant. The accessions were grouped into five clusters of different sizes. Accessions from the southern part of the country (Arsi) distributed overall clusters while those from the northern half (North and South Wello, North Gonder and North Shewa) fell into clusters C₁ to C₃. Cumulative effects of a number of characters dictated differentiation of the accessions into clusters. There was no definite relationship between geographic diversity and genetic diversity as overlapping was encountered in clustering pattern among accessions from different parts of the country. Accessions from different regions might have similar genetic background and those from the same origin might also have different genetic background. Therefore, geographic diversity should not necessarily be used as an index of genetic diversity and parental selection should be based on a systematic study of genetic diversity in a specific population. Genetic distances among most of the clusters were significant that crosses between parents selected out of them are expected to generate desirable genetic recombination. Selection should also consider the special advantages of each cluster and each accession within a cluster. Future germplasm collection, conservation and breeding efforts should focus not only on inter-regional diversity but also on intra-regional diversity.     

Intersite characterization and variability of soil respiration in different arable and forest soils

Summary Soil respiration was investigated in three loamy Orthic Luvisols (two arable, one forest soil), three sandy Haplic Podzols (also two arable, one forest soil) with a modified intersite method according to Lundegardh (1924). The method allows characterization of the CO₂-flux from the soil and interpretation of the different levels with regard to temperature, nutrient and air supply. The method is sensitive to tillage and fertilization effects. In the two arable Luvisols the mean cumulative respiration rate was not uniform compared with the forest soil; in one case it was much higher and in another much lower. CO₂ evolution in the Podzol under spruce was much lower than in the two arable Podzols. In the sandy Podzols 5 replicate measurements gave adequate results, with an error probability of 10%, but in the loamy Luvisols it was necessary to use 10 replicates to specify the same degree of difference. If soil respiration is very high, immediately after fertilization with cattle slurry or dung on arable land, or after litterfall in a deciduous forest, more replicates are necessary.     

烤烟田间生长过程中叶片主要品质指数的变化

对田间状况下烤烟下、中、上3个部位叶片生长发育过程中主要品质指数的变化进行了分析。结果表明:在烤烟田间生长发育过程中,随着烟叶部位的上升,叶片中氮/碱比值表现为“V”型变化;叶片还原糖/总糖比值表现为逐渐升高的变化规律;叶片钾/氯比值表现为“∧”型变化;不同烟叶部位之间氮/碱、还原糖/总糖、钾/氯比值的差异均不显著。随着叶龄的增大,叶片氮/碱比值呈现出下降并趋于稳定的变化规律,叶片还原糖/总糖比值和叶片钾/氯比值的变化无明显规律;不同叶龄之间氮/碱比值的差异极显著,而叶片还原糖/总糖比值、叶片钾/氯比值的差异均不显著。相关分析表明,叶龄与叶片氮/碱比值之间呈极显著负相关,而与叶片还原糖/总糖比值、叶片钾/氯比值之间呈不显著正相关;烟叶中钾/氯比值与氮/碱比值、还原糖/总糖比值之间相关性不显著,还原糖/总糖比值与氮/碱比值之间相关性也不显著。     

豫西地区不同类型农田化肥增产效益及增产潜力研究

 【目的】探讨化肥在豫西地区不同地形农田的增产效益与增产潜力，为引导和实现化肥的优化配置和合理施用、提高豫西地区粮食产量提供参考依据。【方法】采用田间试验，研究了豫西地区平川地、坡平地、坡地等3种典型地形农田化肥施用量对作物产量的影响；并对3种典型农田化肥消费量与粮食产量的多年统计资料进行了分析，提出了二者之间的关系，并由此对豫西地区粮食增产潜力进行了预测。【结果】作物单产以平川地最高，坡平地次之，坡地最低。尽管在3种类型农田上使用化肥均可大幅度增加作物产量，但化肥增产效益以坡地最高，坡平地次之，平川地最低；对3种典型地形农田化肥消费量与粮食产量多年统计资料的分析也获得相同结论。根据田间试验结果对未来豫西地区粮食产量及增产潜力进行的预测表明，当采用本研究中最大施肥量时，豫西地区粮食总产量可达到4.24×109 kg，是2003年该地区粮食产量的2.1倍；并预测在增加粮食产量中，坡地贡献率占50.1%、坡平地占33.7%、平川地占16.2%，坡地和坡平地粮食生产对该地区粮食总产量具有决定作用。【结论】豫西地区3种典型地形农田中化肥增产效益存在差异，以坡地化肥增产效益最大。因此，加强坡地化肥投入，可有效地提高本区粮食总产量，对今后本区粮食的增产具有重要意义。     

10%丁醚脲微乳剂防治小菜蛾的田间药效实验

田间药效试验结果表明:10%丁醚脲微乳剂对小菜蛾有较好的防治效果,156g/hm2对小菜蛾的防效可达98.47%。     

地被菊地栽抗旱性试验研究

[目的]为地被菊的推广提供科学依据。[方法]以4个地被菊品种(铺地雪、落金钱、紫勋章、新红)和早小菊(CK)为材料,抗旱性试验在防雨棚内进行,各品种采取随机区组排列,缓苗成活后,整个生长周期进行控水试验,记录各品种的生长发育状况,比较它们的耐旱能力。[结果]在地栽控水的条件下,地被菊的株高、冠幅的增长率是逐渐降低的。4个地被菊品种的冠幅增长率、分枝能力、花朵数量、地上、地下部干物质量均大于对照早小菊。根冠比大小依次为:新红>落金钱>紫勋章>铺地雪>早小菊。在整个生育周期没有灌溉的条件下,地被菊植株仍然生长健壮且开花繁茂。[结论]新红、落金钱和紫勋章地被菊品种抗旱性表现最好。     

几种杀虫剂对小菜蛾防治效果比较

通过调查死亡数这项指标比较了3种杀虫剂对蔬菜小菜蛾的田间药效,试验结果表明:4000×的1%甲氨基阿维菌素苯甲酸盐乳油对小菜蛾的防治效果最好,其次是1.8%阿维菌素乳油,2.5%高效氯氟氰菊脂微乳剂防治效果较差。     

高肥地小麦再高产综合农艺措施初探

采用五因素二次正交旋转组合设计试验方法,在高肥地对优良小麦新品种临麦2号的主要栽培措施基施纯N量、追施纯N量、P2O5、K2O及基本苗等与小麦产量间的量化关系进行系统研究,通过对建立的产量数学模型的优化与解析,明确了影响高肥地小麦产量的关键因子及实现高产高效优化栽培的综合农艺措施。结果表明,该五因素与其密切相关,增施氮磷肥是实现临麦2号优化栽培的关键,增施磷肥更益于氮肥肥效的发挥,实现优质小麦新品种临麦2号高产高效优化栽培的综合农艺措施是:每公顷基本苗181.8万￣229.2万,基施纯氮量121.95￣141.3kg,P2O5195kg,K2O33.75￣60.75kg,小麦起身期结合浇水追施纯氮71.7￣83.7kg。