茶白星病发生规律及防控模式的研究

本文在石门县系统调查海拔、品种、树龄及栽培影响因子与茶白星病发生的关系,进一步明确了茶白星病发病率与海拔高度正相关,茶园修剪是生态防控茶白星病的有效农艺措施,并提出不同海拔茶区生态防控茶白星病的三种修剪模式。     

玉米间作对辣椒产量和品质的影响

[目的]确定玉米辣椒间作条件下提高辣椒产量和品质的最佳栽培条件。[方法]采用正交设计L9(34)法研究玉米与辣椒间作密度、剪叶剪枝及微肥对辣椒产量和品质的影响。[结果]所考察的因素对辣椒产量的影响程度为:辣椒密度>微肥>剪枝剪叶>玉米密度;辣椒产量高的栽培条件为处理6(种植玉米2.340万株/hm2,辣椒4.650万墩/hm2,不剪枝剪叶,喷施0.2%硫酸锌溶液);对辣椒素含量的影响程度为:玉米密度>剪叶剪枝>微肥>辣椒密度;辣椒素含量高的栽培条件为处理8(种植玉米2.805万株/hm2,辣椒3.315万墩/hm2,不剪枝剪叶,施浓度0.2%硼酸溶液)和处理6;对辣椒Vc含量的影响程度为:微肥>玉米密度>剪叶剪枝>辣椒密度;辣椒Vc含量较高的栽培条件为处理2(种植玉米1.995万株/hm2,辣椒3.315万墩/hm2,辣椒剪枝,喷浓度0.2%硫酸锌溶液)、7(种植玉米2.805万株/hm2,辣椒2.580万墩/hm2,玉米剪叶1/2,喷浓度0.2%硫酸锌溶液)和处理6;辣椒干物质含量较高的栽培条件为处理6。[结论]综合来看,以处理6产量最高,品质较好。     

平衡施肥改善南丰蜜桔品质效应研究

2000～2002年进行了平衡施肥改善南丰蜜桔品质的试验研究,结果表明:适量增施钾肥和合理修剪能显著提高南丰蜜桔的产量及其食用品质,降低疮痂病的发病率和病情指数;施用硫磺有一定的增产作用,但会降低果实的品质。增施钙、镁肥对产量影响不大,但可以提高果实的品质。平衡施肥能显著提高南丰蜜桔的品质和经济效益。     

改形修剪量对矮化红富士苹果枝类构成及结果的影响

以10年生的红富士/M26苹果为材料,研究了改形修剪量对枝类构成及结果的影响。试验表明：随改形修剪量的加大,中长枝比例增加,产量减少,品质改善,成花增加,大小年减轻;但改形过重会引起树势明显反旺,品质下降,成花减少。适宜的改形修剪量应为总枝量的50%~60%。实行强拉枝和加强夏季管理是改形后必不可少的配套措施。     

浅谈广州市城区行道树的修剪技术

从广州城区环境特点出发,结合自身工作实践经验,阐述了广州市行道树修剪的存在问题、行道树修剪的意义、修剪整形的原则、修剪的时机及修剪的方法等。     

切花月季开花枝培养修剪技术研究

选用４ 年生切花月季黄色品种金奖章作为试材,探讨运用修剪手段在春季促生徒长枝并对其进行改造,达到增加切花产量,提高切花质量及调节花期的目的。试验结果表明,春季新梢萌发长至３０ｃｍ 以上、距新梢基部１０ｃｍ 处、粗度达０．５～０．７ｃｍ 的新梢保留开花,其余新梢留６～８ 片叶反复摘心,可兼顾开花和促进徒长枝形成,当徒长枝长至顶花蕾出现时在徒长枝高４０ｃｍ 处短截,然后选留长势相对一致、发育健壮的萌发新梢作为开花枝,可达到调节花期,提高切花产、质量的目的。     

优化型茶树的形成特点和定向调控

本文以中小叶种茶树为材料,从茶树的自身条件出发,提出了“优化型”茶树应具备的5个条件：1.群体有足够和必要的可采芽叶数;2.树冠有适量而均衡的绿色面;3.茶树排列有序,分枝层次分明;4.树体矿质营养丰富,氮、磷、钾比例适当;5.芽叶有适量而协调的生化成分。进而,针对“优化型”茶树的形成条件,将茶树划分为树体扩展、树体定型和树体更新三个时期,按其生长特点,提出了栽培主攻目标和定向调控技术。     

不同花穗整形长度对‘亚历山大’葡萄果实品质的影响

以‘亚历山大’葡萄为试验材料,开花前一周分别留花穗穗尖的3 cm、5 cm、7 cm、9 cm,疏除花穗其余部分,并以不整穗作为对照,测定果实纵横经、果形指数、单果重、可溶性固形物、可滴定酸等指标。研究不同花穗整形长度对‘亚历山大’葡萄果实品质的影响,以期为生产实践提供依据。结果表明‘亚历山大’不同整形长度可在一定程度上提高成熟果实的果实品质。其中保留花穗尖5 cm能显著增加果实横经、果实单果重、提高可溶性固形物含量,且能提高可滴定酸含量,提高果实风味,为‘亚历山大’葡萄花穗最适整形长度。     

桃树修剪后树相参数与产量的相关性研究

以6年生‘燕红’和‘沙红’桃树为试材,调查冬季桃树修剪前后枝量、修剪量、夏剪量,统计分析了其与产量之间的关系。结果表明,在一定的区间内,燕红和沙红的产量随着修剪率和留枝量的升高呈现先升高后降低的趋势,在修剪率为34.63%、43.37%时,产量达到最高,为17.81、7.17 kg;留枝量为134、110时,产量达到最高,为20.58、7.04 kg;长枝率为14.14%、27.35%时,燕红和沙红产量最高,为19.94、7.04 kg;燕红和沙红的产量随着中短枝率的升高整体呈现先降后升的趋势,在中短枝率为59.56%、54.36%时,产量达到最低,为14.20、4.18 kg。通过回归分析得出,燕红和沙红产量与修剪率(燕红17.89%~59.03%、沙红18.90%~62.34%)、留枝量(燕红:94~185个、沙红:73~146个)均呈二次项回归模型;燕红产量与长枝率无相关关系,沙红产量与长枝率(4.61%~27.35%)呈线性关系;燕红、沙红产量与中短枝率(燕红43.28%~73.06%、沙红39.22%~69.58%)呈二次项回归模型。     

Sooty canker,a destructive disease of banyan (Ficus benghalensis L.) trees in landscapes of Kish Island (Iran)

Ficus benghalensis L (banyan tree) has been planted as ornamental tree in parks, landscapes as well as along roads and streets in many southern cities of Iran. During field surveys conducted in Kish Island (Hormozgān province) an unusual decline was noticed on F. benghalensis. Affected trees exhibited bark necrosis, peeled off bark and cankers on branches and aerial roots, yellowing and defoliation, branch dieback and eventually death. A black sooty mass of fungal spores under the bark as well as wood discoloration in cross sections were also observed on infected parts of trees and pruning wood debris. Samples were collected from all affected parts of trees showing disease symptoms, pruning wood debris as well as rove arthropods in close proximity to the trees for the presence of fungal inoculum. In this study 239 Botryosphaeriaceae-like isolates were obtained from discoloured wood tissues, pruning wood debris and from the bodies of collected arthropods. Based on morphological characteristics and DNA sequence data of ITS and tef-1α gene regions, isolates were identified as Lasiodiplodia theobromae and Neoscytalidium dimidiatum. Pathogenicity of both species was performed on the branches of banyan trees and L. theobromae was more virulent, based on the length of necrotic lesions in the wood, than those of N. dimidiatum. This study is the first report of N. dimidiatum associated with sooty canker and dieback of F. benghalensis worldwide. Our study showed for the first time that L. theobromae and N. dimidiatum can also be associated with some arthropods. Our outcomes can improve the management strategies of trunk diseases caused by Botryosphaeriaceae species on ornamental trees in landscapes.