对橡胶树不同品种实行新割制后存在状况的调查与思考

对云南景洪农场六作业区橡胶树RRIM600、PR107、GT1、云研1号等品种实行刺激割胶新割制后的存在状况进行调查,结果表明:胶树的病残株率随着割龄的增加而增高,在开割7年后现存株率、有效割株率及单位面积有效割株数随着树龄的增加而降低;RRIM600在所有割龄段中,相对于其它参试品种表现出较强的适应性,存株率、有效割株率及单位面积有效割株数明显较高、死皮明显较轻。研究提出应在更大范围去深入调查,再认识RRIM600的优良性状,作出新的评价,合理地应用于生产。     

橡胶树优良品种IAN873在云南的适应性

通过对国外橡胶树优良品种IAN873在西双版纳24年适应性观察研究,结果表明:该品种生长快,开割前年均增粗5.65cm,高于对照RRIM600(5.06cm)10.67%;林相整齐,开割时平均茎粗50.5cm,开割率80.2%,分别比对照高2.8cm和10.4%;产胶量中等,1-16割年平均干胶产量1 310kg/hm2,为对照RRIM600(1 969kg/hm2)的66.55%;年平均单株产量为4.0kg,略低于对照RRIM600(4.2kg/年.株)0.2kg;抗辐射寒害能力中等偏下,抗寒力小于GT1,但较RRIM600强;耐割性强,割胶16年后死皮发病率为15.79%,病指14.95,分别比对照(28.79%、27.58)轻13个百分点和12.63。     

东风橡胶分公司橡胶芽接树新割制生产情况调查

通过对橡胶树割胶树位调查,低于20割龄胶树实施新割制,一般表现干胶产量增产和年度间产量变化平稳,累计死皮病率低,而高于20割龄胶树实行新割制、老龄割制和强割制,虽然提高刺激剂使用浓度,仍不能表现干胶增产,同时4～5级死皮率明显增高;品系GT1表现比RRIM更耐刺激,增产幅度大,死皮率更低。     

橡胶优良品种海垦2在云南的适应性

橡胶树优良品种海垦 2在云南省热带作物科学研究所、勐捧农场、孟定农场的适应性试验研究表明 ,1～ 11割年平均单株年产干胶 5.2 7kg ,是对照RRIM6 0 0的 12 2 .8% ;单位面积产量为 2 0 96kg/hm2 ,是对照RRIM6 0 0的138.5%。海垦 2干胶含量高 ,产胶潜力大 ,可以在云南省一类型植胶区大规模种植     

橡胶树矮生高产材料热研87-4-26选育初报

热研87－4－26为热研88－13×热研217杂交后代第3、4割年平均株次干胶为111.89g，干胶产量是对照的225.1％。生长比对照RRIM600慢，11年生时全树高13.7m，比对照矮15%，是一个早熟、高产、稳产的矮生材料。     

海南东部垦区部分农场橡胶树叶片营养元素含量分析

对海南省东部部分农场PR107和RRIM600不同产量水平的成龄胶园叶片养分分别进行了研究,结果表明,两个品种的高、中、低产胶园叶片养分状况都存有明显差异,PR107品种高产胶园的全氮和全磷显著高于中、低产胶园;RRIM600不同产量水平的胶园中全钾和钙存在显著差异。高产胶园中,PR107和RRIM600品种间叶片养分含量存在显著差异,因此,要因树施肥,合理配比,达到增产的目的。     

西双版纳橡胶树死皮病症状调查

调查西双版纳RRIM600和GT1两个品种橡胶树的不同割龄段死皮树的症状,根据排胶、割线颜色、树体状况三个方面的症状表现,死皮病典型症状可归纳为点状排胶或割线干涸,割线褐色、暴皮三种表现,其中RRIM600死皮树表现割线干涸和点状排胶的分别为41.7%和45.3%,割线表现内褐、褐皮平均分别为42.7%和35.2%,树体多数表现为块状暴皮,平均达44.8%;GT1死皮树症状以割线干涸为主,占61.9%,其次为点状排胶,占23.9%,割线表现为褐皮、内褐的分别占29.5%和44.9%,树体多数表现为短裂纹状暴皮,平均达34.1%。文章还对死皮病病程、诱因进行探讨。     

橡胶树四种有机肥肥效试验

通过2006-2007年两年对橡胶树品种RRIM600、GT1的4种有机肥肥效试验结果:千州有机—无机复混肥处理的两个橡胶树品种的干胶含量显著高于生产常规施肥(对照)和其它肥料处理;RRIM600的平均刀次干胶产量显著高于生产常规施肥(对照)和其他肥料处理。     

巴西橡胶新种质鉴定及利用研究初报

对从科特迪瓦和CIRAD -CP引进的 198个巴西橡胶新种质和 10个IRCA橡胶树新品种在云南植胶区的农业气象条件下进行适应性鉴定。这些新种质和新品种生长表现良好。经试割 ,新种质几乎无胶可收 ,新品种试割6个 ,有 4个产量超过RRIM60 0 ,抗寒能力普遍差。     

橡胶树优良无性系热研8-79选育初报

初级系比１８年和高级系比１１ 年的试验初步表明,热研８－ ７９是一个干胶含量较高且产量高的橡胶树优良新品种。在高级系比区,１～３ 割年平均年产干胶１ ８３９ｋｇ／ｈｍ ２ ,为对照ＲＲＩＭ６００的２０６．７％     

Effects of <Emphasis Type="Italic">Inga densiflora</Emphasis> on the microclimate of coffee (<Emphasis Type="Italic">Coffea arabica</Emphasis> L.) and overall biomass under optimal growing conditions in Costa Rica

The advantages of associating shade trees in coffee agroforestry systems (AFS) are generally thought to be restricted mostly to poor soil and sub-optimal ecological conditions for coffee cultivation whereas their role in optimal conditions remains controversial. Thus, the objective of this study was to investigate, under the optimal coffee cultivation conditions of the Central Valley of Costa Rica, the impact of Inga densiflora, a very common shade tree in Central America, on the microclimate, yield and vegetative development of shaded coffee in comparison to coffee monoculture (MC). Maximum temperature of shaded coffee leaves was reduced by up to 5°C relative to coffee leaf temperature in MC. The minimum air temperature at night was 0.5°C higher in AFS than air temperature in MC demonstrating the buffering effects of shade trees. As judged by the lower relative extractable water (REW) in the deep soil layers during the dry season, water use in AFS was higher than in MC. Nevertheless, competition for water between coffee and associated trees was assumed to be limited as REW in the 0–150 cm soil layer was always higher than 0.3 in shaded coffee compared to 0.4 in monoculture. Coffee production was quite similar in both systems during the establishment of shade trees, however a yield decrease of 30% was observed in AFS compared to MC with a decrease in radiation transmittance to less than 40% during the latter years in the absence of an adequate shade tree pruning. As a result of the high contribution (60%) of shade trees to overall biomass, permanent aerial biomass accumulation in AFS amounted to two times the biomass accumulated in MC after 7 years. Thus provided an adequate pruning, Inga-shaded plantations appeared more advantageous than MC in optimal conditions, especially considering the fact that coffee AFS provides high quality coffee, farmers’ revenue diversification and environmental benefits.     

国外橡胶树优良品种RRIM712生产适应性系比试验

在云南植胶区对橡胶树优良品种RRIM712的27年生产适应性试验表明:RRIM712生势中等,产量中等,抗辐射型寒害能力差,与对照RRIM600相当;割胶刺激反应中等,死皮病情、刺激类型与RRIM600相近,属一类刺激品种。     

不同基因型橡胶树花药体胚发生能力的差异分析

目的 探明不同基因型橡胶树的体胚发生能力差异,为优化橡胶树不同品种体胚发生体系提供理论基础。 方法 以国家橡胶树种质资源圃保存的32个橡胶树主栽品种及其亲本为材料,通过系谱分析明确品种间的遗传关系,并以花药作为外植体诱导愈伤组织并进一步诱导体胚发生,结合体胚诱导率和遗传关系分析不同基因型体胚发生能力的差异。 结果 对32个橡胶树品种进行系谱分析表明：PR107、GT1、PB86、Tjirl、海垦1、天任31-45、合口3-11这7个品种为初生代无性系,其余25个品种中的23个与以上7个初生代无性系中的1 ～ 3个存在亲缘关系,表明我国橡胶树主栽品种亲本来源狭窄。结合系谱和体胚发生结果分析表明：橡胶树品种的体胚发生能力与亲本来源密切相关,亲本体胚发生能力决定其子代品种体胚发生能力。父母本均为难诱导体胚发生品种时,其杂交后代多数难诱导体胚发生;父母本中含1个易诱导体胚发生品种,即使另1个亲本为难诱导体胚发生品种时,其杂交后代多数体胚发生效率高,但这些后代间体胚发生频率差异显著,且存在超亲现象,推测橡胶树体胚发生是由多基因参与控制的。GT1、天任31-45、93-114和RRIM513等为难诱导体胚发生品种,以其为亲本来源的杂交后代多数难以诱导体胚发生（如云研77-2、云研77-4、云研73-46、保亭1-285、湛试32713、热研217）,而PB86、RRIM600、热研88-13和海垦1等为易于诱导体胚发生品种,以其为亲本之一的杂交后代多数体胚发生效率高（如大丰95、海垦2、热研917、热研73397、热研879、热研918、徐育3、徐育141-2）。 结论 本研究发现,橡胶树体胚发生能力存在明显的基因型差异,且这种差异可遗传。依据体胚诱导率和遗传关系,本文将橡胶树亲本的体胚形成率同子代的诱导率结合进行分析并分组,为利用基因型分组优化橡胶树栽培品种的体胚发生体系提供了依据。     

Spatial distribution of Hevea brasiliensis trunk phloem necrosis within a plot: aggregation but no evidence of constraint on cumulated growth

Trunk phloem necrosis (TPN) is a major constraint in rubber (Hevea brasiliensis) plantations. Current knowledge supports a scenario of a multi‐factor physiological ‘disease’ caused by an accumulation of endogenous and exogenous stresses. Without evidence of a pathogen, the apparent spread of the syndrome from tree to tree along the planting line, strongly suggested the implication of a major local soil constraint. The objectives of the study were to address, within a plot, three points of the above scenario: the short‐distance aggregation of affected trees; their correspondence with local micro‐areas facing the highest environmental constraints; and the relative weakness of TPN trees that had accumulated several stresses since planting. The study was conducted in a young rubber tree stand (clone RRIM 600) of Northeast Thailand, where the number of TPN affected individuals was 8% after 3 years of tapping. Trunk girth and trunk basal area were used as indicators of local environmental constraints. Spatial patterns were analysed using the framework of marked point processes and K functions. The results confirmed the short‐distance aggregation of TPN affected trees. But, TPN trees were not located within micro‐areas where trees had a lower trunk basal area than average. Hence, the clusters of TPN do not occur in the most constraining environmental micro‐areas of the plot in terms of growth since planting. Moreover, from comparison of girth, current girth increment and height of bark consumption, we infer that TPN trees were not smaller and less vigorous than other trees before the syndrome outbreak. Finally, our conclusions mean the previous scenario driven by major soil constraints becomes a ‘more complex scenario’ in which specific soil conditions (not the most constraining in term of cumulated growth), possibly in interaction with inter‐individual competition, induce a late and subtle stress favouring a necrotic reaction against tapping stress.     

橡胶树砧木家系苗期生长性状变异分析

在西双版纳采集优良无性系RRIM600、GT1和IAN873开放授粉种子(花粉来源复杂),繁殖成3个家系用作砧木试验,对其实生苗木逐株编号,在嫁接前测量6个性状指标并进行变异分析。结果表明,在家系内株高、地径、每蓬叶数、大叶柄长、小叶长、小叶宽等6个性状变异系数为11.19%~27.17%;IAN873种子苗木平均株高为222.14 cm,平均地径为22.48 mm,显著大于RRIM600和GT1种子苗木的株高和地径(P<0.01);3个家系苗木株高和地径基本符合正态分布,株高和地径与叶子4个性状相关密切。橡胶树的这3个家系间和家系内单株间都存在丰富的遗传变异。     

Optimizing Tapping-Tree Density of Rubber (<Emphasis Type="Italic">Hevea brasiliensis</Emphasis>) Plantations in South China

Tapping-tree density in rubber plantations affects the production of dry rubber. Farmers can estimate rubber productivity when they know with certainty the number of tapping trees within a plantation and can therefore increase productivity through optimized planting schematics. Historical data on planting distance between trees and between rows, planting density (trees/ha) and tapping-tree density (number of trees under tapping for latex harvest per hectare) from 1952 to 2014 have been collected for plantations in the Hainan, Yunnan and Guangdong provinces of South China. A plantation survey was conducted to collect more detailed data on current tapping tree and planting densities in various plantations in the three provinces. Planting density and row spacing are found to have increased with rubber tree planting time and plant spacing to have declined from 1952 to 2014. Tapping-tree density of rubber plantations from 1955 to 1995 in South China ranges from 270 to 345 tree/ha, averaging 300 trees/ha. Strong typhoons and cold snaps are important drivers of fluctuations in tapping-tree density. The factors driving tapping-tree density are similar across the three provinces but the degree of change differs between provinces. Tapping panel dryness (due to tapping beyond the natural limit of the rubber tree productivity), severe wind damage and cold damage are the major factors resulting in loss of tapping trees in plantations in South China. These results suggest that a combination of environmental management for extreme weather and targeted breeding could improve tapping-tree density in rubber plantation and therefore dry rubber yield per unit area.     

Growth and yield of coffee plants in agroforestry and monoculture systems in Minas Gerais, Brazil

This research compared coffee plants (Coffea arabica L.) grown in an agroforestry and monoculture systems. Data were collected during two years, on vegetative growth, reproductive development, nutritional status and yield of coffee, besides monitoring air temperature and the tree growth. All trees in agroforestry system increased in growth, resulting in a reduction in the magnitude of the diurnal temperature variation and also maximum temperature. Coffee plants in agroforestry system had less branch growth and leaf production, more persistent and larger leaves, and presented earlier flowering, with a smaller number of productive nodes and flower buds, leading to smaller berry yield than plants in monoculture system. In both systems, the coffee plants showed adequate leaf nutrient levels, except for P and K. The yield of 2443 kg ha^-1 of coffee from the monoculture was greater than 515 kg ha^-1 of coffee from the agroforestry system.     

Performance of different rubber tree clones against South American leaf blight (Microcyclus ulei)

This study was aimed to evaluate the behaviour of eighteen clones of Hevea brasiliensis (rubber) against South American leaf blight and to study progress of the disease. The experiment was conducted in Cachoeiro de Itapemirim‐ES, where 18 clones were evaluated. The experimental design was a randomized block with four replicates; each experimental unit consisted of three plants. Evaluations were performed at 15‐day intervals on 30 leaflets per tree. Disease incidence was quantified and infection classified according to the stages of development and type of damage. Leaf blight occurred during the entire experimental period; however, disease intensity varied with the resistance level of the clones and the time of year. Clones FX 3864, RRIM 725, RRIM 711, IAC 300 and IAN 873 exhibited the highest resistance to leaf blight.     

Growth performance and gum arabic production of Acacia senegal in northwest lowlands of Ethiopia

Despite the wide distribution of natural stands of Acacia senegal in Ethiopia, commercial exploitation of gum arabic is constrained by lack of tapping and development techniques. We evaluated the gum arabic yield from natural stands of A. senegal and the growth of 6 provenances in different parts of the country. For the gum yield evaluation from natural stands, four tapping positions and three tapping seasons were tested in a factorial RCB design. The second experiment in Metema evaluated survival and growth of six provenances. A. senegal trees in natural stands respond well to tapping if tapped during the appropriate season and at the correct position on the tree. The mean gum yield did not vary significantly by tapping season (p=0.63). Higher mean yield was, however, collected from trees tapped in October (96 g·tree^?1 per two harvests). The mean yield differed significantly (p=0.009) between the tapping positions. Mean separation (α=0.05) shows that trees tapped at mid stem gave higher yield (160 g·tree^?1 per two harvests). The interaction effect of tapping season and position was not significant. Higher mean yield ((70 ± 112) g·tree^?1) was recorded in mid October-mid stem in two harvests. The second experiment indicated statistically significant difference in mean survival (p=0.0298), height (p=0.000) and root collar diameter (RCD), (p=0.012) between the six provenances. Highest survival, height and root collar diameter growth was observed from Abderafi provenance (100%, (148±11) cm, (38±11) mm, respectively). We recommend October and mid-stem and branches as appropriate tapping season and position. We recommend planting of the Abderafi provenance for the study area due to its superior growth and survival. Our study contributes to the proper selection of provenances for plantation development and improved tapping technology for better production of gum arabic in the country.