Soil pH in fruit trees in relation to specific apple replant disorder (SARD). II. The first five years at the Wageningen research plot

Field plots were established with 4 target pH values, viz. 4, 5, 6 and 7, to study the effect of pH on specific apple replant disorder (SARD). The target pH levels were not stable and frequently showed fluctuations. Although no significant differences have been found on tree performance, the development of the trees on the plots with the lowest pH level was better than those at higher pH levels.     

苹果凹果类病毒(ADFVd)的检测与序列分析

采集新疆焉耆地区的老果园的苹果树枝条、叶片和韧皮部,利用自行设计的方法提取总RNA,根据GenBank中的X99487序列设计引物,利用RT-PCR技术扩增出苹果凹果类病毒(ADFVd)特异条带,通过回收克隆测序,结果表明,获得的7条序列,有5条同源性很高,均在98%以上,另外2条的同源性只有85%左右,这7条序列均已在GenBank中登录(登录号:EU031497_EU031503)。在此基础上利用插入ADFVd目的DNA的质粒为模板,成功合成了地高辛标记的cDNA探针,该探针能很好地用于ADFVd的检测。同时利用原位RT-PCR技术,做了进一步检测,证明苹果叶片中有苹果凹果类病毒存在,主要分布在叶肉细胞的细胞核中。     

Light distribution in apple orchard systems in relation to production and fruit quality

Summary

The effect of tree density (2000, 2667, and 4000 trees per ha) and the ratio of between to within-row distance (1:1, 2:1, and 3:1) on light interception, fruit production, colour and individual fruit weight was evaluated in a ten-year comparative field study with apple at two sites in The Netherlands (51° 30′ and 52°0′ N) and one site in Denmark (55°30′). For each combination of tree density and rectangularity, trees were pruned at three heights (1.50, 1.88, or 2.25 m). Fruit production over nine years and seasonal incoming radiation between bloom and harvest were 20 and 15% greater in The Netherlands. Climate-based estimates of potential production as provided by a crop-growth model, predicted 18% higher fruit production in The Netherlands. Production was proportional to light interception and increased with tree density, but the amount of well-coloured fruit per ha in later years did not increase with planting density. With more than 70% light interception in later years, a large proportion of shade within the canopy was found. Fruits were smaller and less coloured at the Danish site. Fruits were more coloured in the taller and more open trees, even at the highest tree densities. Plantings with 1:1 and 2:1 between-to within-row distances intercepted more light and had a more uniform light distribution than 3:1 designs. This led to higher fruit production and better fruit colour. Fruit weight was not influenced by tree density, rectangularity, or tree height.     

巴基斯坦毛刺线虫在苹果园的发生及其与树势的关系

研究表明，导致北京南口农场苹果短粗丛根病的巴基斯坦毛刺线虫（Ｔｒｉｃｈｏｄｏｒｕｓ　ｐａｋｉｓｔａｎｅｎｓｉｓ）在所调 查的４５个果区中的３１个果区大量发生，总样品频率和最高群体密度分别为 ４７． １％和 ５３６条／２００ｍｌ土壤。各 区平均群体密度在１～２８２条／２００ｍｌ土壤之间，以第４０区的密度最高。线虫群体在３～５月间数量很少，６～ ７月大量发生，８～９月开始下降。弱树根围群体数量最多，达５２０条／２００１ｍｌ土壤，半死树次之，旺树和死树 根围线虫数量最少，分别为 ６４条／２００ｍｌ土壤和 ８０条／２００ｍｌ土壤。     

地面覆盖对苹果树体生长和果实品质的影响

【目的】揭示苹果树叶片光合参数、树体生长量和果实品质对不同覆盖物的差异性反应,为苹果园地面管理覆盖物的合理选择提供参考依据。【方法】以辽宁省果树科学研究所自主选育的‘望山红’/‘辽砧109’组合苹果树为试材,果园地面分别覆盖农用地毯、碎木屑和园艺地布,以清耕为对照,调查地面覆盖后土壤地温、土壤含水量、叶片光合参数、树体生长量、果实品质的差异。【结果】2016年、2017年农用地毯、碎木屑、园艺地布、淸耕(CK)土壤温度随土层深度增加而降低,土壤含水量随土层深度增加而升高。与清耕(CK)相比,园艺地布覆盖提高土壤温度,农用地毯和碎木屑覆盖降低土壤温度;农用地毯、碎木屑、园艺地布覆盖能提高土壤含水量。3种覆盖处理均能提高叶片净光合速率、水分利用效率、叶绿素相对含量。其中,农用地毯覆盖后叶片净光合速率、水分利用效率、叶绿素相对含量变异系数最小、稳定性优于其他处理,而碎木屑覆盖季节性差异明显、变异系数高、稳定性差。3种覆盖处理均能提高单叶质量、叶片厚度、树高、覆盖率、总枝量,影响枝类组成比例。其中,农用地毯覆盖后单叶质量、叶片厚度、覆盖率、总枝量、中枝、短枝比例等指标高于同期其他处理,而长枝比例低于其他处理。春季园艺地布覆盖后的新梢长度显著高于其他处理,而夏季农用地毯和碎木屑覆盖后的新梢生长速度快。农用地毯覆盖后果实单果质量、硬度、可溶性固形物、固酸比等指标最高,其次为碎木屑。农用地毯、碎木屑、园艺地布覆盖后显著提高果面红色着色程度,提高果实中葡萄糖、果糖、蔗糖、莽草酸含量,降低苹果酸、柠檬酸含量。【结论】综合比较3种覆盖物对土壤温度、土壤含水量、植株叶片参数、树体生长量和果实品质的影响,作用效果从高到低分别为农用地毯、碎木屑和园艺地布。     

果树化学疏花疏果技术综述(续)

化学疏花疏果是克服果树大小年与提高果品质量的一项重要手段。不同的化学药刘的疏除机理及使用方法有很大差异,在使用时应注意。目前化学疏花疏果技术主要在苹果、梨、桃、枣、杨梅上使用较多,效果也较好。树势、气候等因素影响化学疏除剂的使用效果。     

'红富士'苹果幼树早丰优质栽培技术(Ⅱ)

1 ‘红富士‘苹果的高接换头 　　‘红富士‘虽具有很多优点,但也应看到其抗寒性较差的弱点,这对我国气温较低的地区,如辽宁、河北、山西、陕西、甘肃等省的部分地区的红富士苹果栽培来说,是应当注意的一个问题.从近几年‘红富士‘苹果生态表现和全球气温变暖的趋势来看,我们不能否定在1月份平均气温-10℃线栽培红富士的可能性,但生产实践证明,高接换头技术,具有明显提高‘红富士‘苹果树抗寒性的作用.因此,先栽抗寒性较强的品种,然后对其换头,成为较寒冷地区发展富士苹果的一个新途径.……     

液体授粉对苹果坐果率及果实的影响

苹果液体授粉试验结果表明:液体授粉的花朵坐果率较自然授粉提高61.41%,花序坐果率提高13.73%;偏斜果率较自然授粉降低19.6%,果实纵径较自然授粉增加6.43 mm,果实横径较自然授粉增加8.27 mm。     

Regulated deficit irrigation in `Clementina de Nules' citrus trees. I. Yield and fruit quality effects

Summary

An experiment on Regulated Deficit Irrigation (RDI) was performed during 1995 and 1996 in a ten year old, drip-irrigated `Clementina de Nules' mandarin orchard in Moncada, Spain. Treatments consisted of a control, where irrigation was applied without restriction during the whole year at 125% ET_lys and RDI treatments where irrigation was reduced to 25% or to 50% of crop evapotranspiration measured by a weighing lysimeter (ET_lys) during one of the following periods: I) flowering and fruit set (spring, 20 March to 3 July in 1995, and 1 April to 1 July in 1996); II) initial fruit enlargement phase (summer, 4 July to 7 August in 1995, and 2 to 28 July in 1996), and III) final fruit growth and maturation phases (end of summer–autumn, 8 August in 1995, and 29 July in 1996 to harvest). An additional treatment, denominated 50%–Year, was irrigated at 50% ET_lys during the whole year. The effects of the treatments on yield and fruit quality in relation to tree water status (pre-dawn (c^a) and midday (c^md) leaf water potential, and their time integral) show large differences in sensitivity to water stress according to phenological stage. The critical periods were the flowering and fruit set phases. The main treatment effects during each period were: In spring, a decline in c^a and c^md with respect to the control of only 0.1 to 0.2 MPa reduced yield by 62% and 28%, respectively for the 25% and 50% levels, due to an increased ``June drop'' and consequent fewer fruit harvested per tree. Final fruit size and quality were similar to those of the control. In summer, RDI treatments allowed water savings between 7 and 14% without affecting yield or fruit quality, providing that a threshold value of c^a–1.3 MPa is not surpassed. In autumn, for the 25% and 50% levels there was a 25 to 11% reduction of fruit size, respectively, with some external peel disorders (creasing) which reduced fruit quality, even at the lower water stress levels reached in the 50% treatment during this period (c^a 20.64 MPa and 20.83 MPa in 1995 and 1996, respectively). In treatment 50%–Year, where water application was 44% of that in the control, minimum c^a values were around 20.6 MPa and 20.8 MPa in 1995 and 1996, respectively. Tree growth was reduced in both seasons and average yield decreased by 17%. Yield loss was due to smaller, not fewer fruit. This treatment increased TSS and acids in the juice, without affecting the maturity index or creasing. However, in the current market situation, this irrigation strategy could be recommended only as a long-term one in cases of very high water prices.     

苹果无公害标准化施肥方案及配套专用肥研究

在制定出果园1a的施肥方案上,根据土壤条件配制专用肥,从横向和纵向两方面实施果园平衡施肥技术,结合新型肥料生产技术的应用,达到提高肥料利用率,减少肥料投入量,防止过度施肥对环境造成危害等目的。结果表明,以《无公害食品苹果生产技术规程》中推荐的施肥量为对照,在专用肥氮、磷、钾的施入量分别减少1/3和1/2的情况下,补充适当微量元素和有机质,取得了树体营养、产量和品质均显著提高的效果。施肥方案与专用肥的结合,是实现果园标准化施肥的有效途径。     

Light penetration,growth, and fruit productivity in ‘Fuji’ apple trees trained to four growing systems

The study was conducted to document the range in soil nutrients, trunk and shoot growth, leaf characteristics and nutrient content, flower bud characteristics, yield, fruit quality, disease occurrence, light penetration, and shoot bark color in a 15-year-old ‘Fuji’ apple (Malus × domestica Borkh.) orchard on M.26 rootstocks trained to four growing systems. SS trees naturally growing had greater width and volume than the LT lightly heading, MLT heavily heading, and S trees thinning and bending. LT trees had more upward terminal shoots at old branches, large numbers of lateral shoots, and longer total shoot length. Leaf [N], [P], and [K] were the lowest for the MLT trees. SS and S trees had greater flower bud density and fruit yield, but LT trees had poor fruit color and less soluble solids and firmness. Percent light penetration into the canopy was the highest with the S system but not different from MLT or SS. The lowest was for the LT system, however, it was not statistically different from MLT or SS.     

Watercore in Japanese pear (Pyrus serotina Rehder var. ‘Culta’ Rehder). I. Description of the disorder and its relation to fruit maturity

Out of 119 Japanese pear cultivars and selections and 12 Chinese ones and their 9 hybrids, 30 cultivars and selections showed a physiological disorder in the flesh of the fruit while still on the tree. The affected tissues were generally watery and translucent, and tasted sweet, but in some cultivars the area was slightly brown and tasted bitter. Cavities and/or pithiness developed in these areas both on the tree and during storage. Distribution of affected tissues on a transversely cut surface at the equator of the fruits showed 5 different types of appearance. In most cases the affected tissues were observed near or around the vascular bundles.In the most susceptible selection ‘93-3’, a higher percentage of affected fruits and severer symptoms were observed in the later-picked fruits. Greater severity of disorder was also found in the softer and more yellowed fruits with the more soluble solids. Because of several properties common to both the watercore of apples and this disorder, the term ‘Watercore in Japanese pear’ was chosen to describe it.     

果树树形的形成机制与调控技术研究进展

树形培养与维护是形成理想树体结构的基础。不同果树种类或同一种类在不同栽培条件下的适宜树形有所差异,筛选与应用具有通风透光、高光能利用率、低成本、丰产、稳产、优质等特点的适宜树形是大多数果树生产者的共同目标。果树树形含自然树形和人工培育树形,众多研究者通过不同树形结构特点及其修剪效应的对比分析,逐步完善果树树形培养与维护的技术体系,并提出冠层分枝与节间长度遗传特点、激素与矮化基因调控树形的机制。为此,本文对果树的树形类型、形成调控机制、人工整形修剪技术,以及树形的培养与维护等方面的研究现状进行了综述,并对省力化机械修剪、树形形成调控机制及适宜树形的合理评价方法等进行了展望,以期为果树树形培养和科学修剪提供参考。     

Soil pH effects on yield and fruit size of two rabbiteye blueberry cultivars

The effects of soil pH on yield and average berry weight of rabbiteye blueberry cvs Delite and Tifblue were investigated. Over a three year period, the higher soil pH decreased from 6.5 to 5.9, but the total yield of both cultivars decreased more than 60% as soil pH increased from 4.5 to 6.5 in the first two years and to 5.9 during the last year. Percent marketable yield was less influenced by the change in soil pH than was total yield. ‘Tifblue’ produced more fruit and had higher marketable yields, but the fruit size determined by average berry weight was smaller than ‘Delite’. When the soil pH was at a more desirable range for maximum yield (4.5 to 5.3), ripening was more uniform for both cultivars. This study illustrated that: (a) two rabbiteye blueberry cultivars differed in tolerance to alkaline growing conditions, (b) the response of the two cultivars to the change in soil pH varied from year to year, and (c) total yield of both cultivars was maximized when soil pH was below 5.0.     

New approaches to the alleviation of barewood in young apple trees

Summary

Precocity is particularly important for the economic production of intensively planted apple trees. Unfortunately some cultivars show a propensity for barewood on young trees, which limits early production on 2 year-old spur sites. The new cultivar, ‘Scifresh’ (Jazz?) has shown serious problems of barewood under New Zealand conditions on M.9 and M.26 rootstocks. Barewood has been associated with excessive flowering on feathers and 1 year-old wood. Weak flower clusters develop towards the base of the shoots which do not set fruit and drop off, leaving blind buds. Although there are larger, more well-developed flower clusters on the distal parts of the 1 year-old shoots, cropping these can result in spur extinction. Therefore, in both cases, there is a lack of spur development for the following season resulting in barewood. Experimental treatments have focused on: 1) the effect of timing (January-May) and concentration (400 and 133 mg l^–1 gibberellic acid GA₃) sprays in the nursery to reduce flowering on 1 year-old wood; and 2) the effect of concentration and timing of localised cytokinin applications in the Spring to re-invigorate blind buds. Two applications of 400 mg l^–1 GA₃ in late January and late February in the first year in the nursery were effective in eliminating flowering on “knip boom” trees in the following Spring after cutting back. Two applications of 400 mg l^–1 GA₃, in early and late January, to “knip boom” trees in their second year in the nursery reduced flowering by over 40% when the trees were planted in the orchard. Twelve months later these trees showed an increased density of spur flowers on the original feathers. Aqueous solutions of the cytokinins benzyladenine and thidiazuron, at 500 mg l^–1 or 2500 mg l^–1 respectively, were applied by brush, prior to, during and post-budbreak, to sections of barewood on 2 year-old or 3 year-old wood on main branches of ‘Scifresh’/M.9 trees. Thidiazuron (at 2500 mg l^–1) was far more effective than benzyladenine at inducing growth of dormant buds, even resulting in multiple bud-breaks at individual sites.     

二斑叶螨在苹果树上的发生与防治

针对苹果树上二斑叶螨的危害情况和发生规律进行了田间药剂筛选试验。结果表明，在泰安，二斑叶螨1年发生10～12代，第1代卵的孵化盛期在4月中下旬，正值苹果谢花后，9～10月陆续下树越冬。防治时宜在早春越冬雌成螨出蛰后喷1．8％齐螨素乳油5000倍液；苹果谢花后喷15％扫螨净乳油2000倍液杀1卵；夏秋二斑叶螨世代重叠时可选哒螨灵与阿维菌素混合喷雾。同时结合清除田间杂草等农业防治措施，即可有效地控制二斑叶螨的危害和蔓延。     

果树裂果原因及防治技术研究进展

果树裂果现象在果实发育过程中普遍存在,本文从果实的遗传因素、生理特征、矿质元素、外界环境、栽培方式等方面对果实裂果发生原因进行了分析,并提出相应防治对策。     

果树化学疏花疏果技术综述

化学疏花疏果是克服果树大小年与提高果品质量的一项重要手段。不同的化学药剂的疏除机理及使用方法有很大差异,在使用时应注意。目前化学疏花疏果技术主要在苹果、梨、桃、枣、杨梅上使用较多,效果也较好。树势、气候等因素影响化学疏除剂的使用效果。     

烟台苹果树势衰弱的原因及对策

烟台苹果面积大,产量高,历史悠久。截至2018年底,烟台苹果种植总面积达到18.84万hm^2,产量达到535.1万t,连续10年位列全国果品区域公用品牌价榜榜首,是名副其实的“中国第一个苹果”。如何确保烟台苹果产业的持续健康发展,已成为烟台苹果产业发展面临的重要课题。笔者就烟台苹果生产中普遍存在的树势衰弱问题进行了调研,并提出预防苹果树势衰弱和弱树转壮对策。以供参考。     

Cellular wall metabolism in citrus fruit pericarp and its relation to creasing fruit rate

Citrus creasing results in serious economic loss in many citrus orchards. Based on the different incidence of creasing, two sweet orange cultivars ‘Hong Jiang’ (grafting chimaera of which flesh is mostly from Citrus reticulata Blanco and peel is from Citrus sinensis Osbeck in) and ‘An Liu’ (Citrus sinensis Osbeck) were used to investigate the creasing rate. The ultrastructure in cellular wall, cellular wall component, cellular wall degradation-related enzymes and expansin (Ct-Exp1) of sweet orange during fruit ripening in field were comparatively analyzed. ‘Hong Jiang’ sweet orange had a higher creasing rate than ‘An Liu’ during ripening. The activities of polygalacturonase, cellulase and pectinesterase in cellular wall of ‘Hong Jiang’ increased more markedly compared with ‘An Liu’. The increases in the content of soluble pectin, ionically associated pectin, covalently bound pectin, hemicellulose and cellulose of ‘Hong Jiang’ were higher than those of ‘An Liu’. Furthermore, the enhanced degradation of the ultrastructure in the albedo cellular walls was observed in ‘Hong Jiang’. Moreover, the northern blot analysis indicated that the Ct-Exp1 gene expressed more strongly in peel of ‘Hong Jiang’ than ‘An Liu’ during fruit ripening. These data suggest that enhanced loss of pectin and cellulose in the cellular walls of peel tissue of sweet orange could result in fruit creasing.