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。     

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     

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。     

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％     

Intra- and inter-clonal tree growth variations of Hevea brasiliensis

We evaluated the effects of planting densities (500, 1,000,1,500 and 2,000 trees·ha-1) on tree growth performance (diameter atbase, diameter at breast height, and clear bole height) of two clones(RRIM 2020 and RRIM 2025) of nine years old plantations of rubber tree(Hevea brasiliensis Muell. Arg) in Malaysia. For the four planting densities of the two clones, basal area and diameter at breast height declined with increasing planting density. Clear bole heights were greatest at 1,500 trees·ha-1 and lowest at 500 trees·ha-1 for the clone RRIM 2020, andat 2,000 trees·ha-1 and 500 trees·ha-1 for clone RRIM 2025. We conclude that the ideal planting density is 2,000 trees·ha-1 for obtaining high volume of wood production and 500 trees·ha-1 for high wood quality.     

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。     

Evaluation of Brazilian wild Hevea germplasm for cold tolerance:genetic variability in the early mature growth

Hevea brasiliensis is a commercially cultivated species for its natural rubber(NR) latex in South East Asian countries. To meet the ever-increasing demand, NR cultivation has been extended to non-traditional regions due to the limited scope of further expansion in traditional rubbergrowing areas in India. These areas are often confronted with various abiotic stresses, especially high and low temperatures, which cause reduction in plant growth, thereby increasing its uneconomical immaturity period. Eighteen wild Hevea accessions along with two modern clones RRII203 and PB 235 and two check clones RRIM 600 and Haiken 1 were evaluated in the early mature growth phase.The site was at Nagrakata, West Bengal, the sub-Himalayan cold-prone region of India. In Hevea, crop production is governed by two major factors, growth-vigor and production capacity. Growth-vigor is of special importance because the production of rubber is a process linked with the early growth of the plant, which results in early tappability and early economic gains. The genotypes exhibited highly significant clonal differences(P = 0.05) for all the growth traits. Tappability percentage in the seventh year, ranged from 0.33 %(AC 3074, AC 3075, AC 3293) to 89.67 %(RO 2727). The most vigorously growing accession(RO2727) reached tappabile girth early in the seventh year when the girth of plant ranged from 22.38 cm(AC 3293) to53.12 cm(RO 2727). The general mean was 43.32 cm, and the similar growth trend was exhibited by these accessions in the tenth year also. Annual girth increment(cm a-1) over3 years ranged from 1.81 cm(AC 3075) to 6.80 cm(RO2727). The mean winter girth increment(cm a-1) over4 years ranged from 0.13 cm(AC 3075) to 0.96 cm(RO2727) as compared to the check clone RRIM 600(1.11 cm)and Haiken 1(1.10 cm). Wide differences between the phenotypic coefficient of variation(50.29) and genotypic coefficient of variation(24.82) were observed for winter girth increment. Girth in the tenth year recorded the highest heritability(87 %). Girth was significantly correlated with the other growth traits. The top 30 % of the potential accessions showing high growth vigour and early tappability under cold stress were identified. These ecotypes/selections have high potential value for the development of coldtolerant clones for these regions and also in broadening the genetic base of the present-day cultivated rubber.     

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。     

Contrasting strategies to cope with chilling stress among clones of a tropical tree, Hevea brasiliensis

Eight Hevea brasiliensis Muell. Arg. clones (GT1, YUNYAN77-4, IRCA707, IRCA317, PB217, PB260, PR107 and RRIM600) were compared for their tolerance towards chilling stress. Net photosynthesis (Pn), stomatal conductance (Gs), optimal and effective photochemical efficiencies (F(v)/F(m) and ), non-photochemical quenching, cellular lysis and leaf necrosis were measured on trees chilled at 10?°C for 96?h, as well as upon recovery at 28?°C. In addition, ascorbate peroxidase, catalase, dehydroascorbate reductase, glutathione reductase, monodehydroascorbate reductase and superoxide dismutase activities were monitored. Clone RRIM600 appeared to be the most tolerant, because it showed no cellular lysis or leaf necrosis and the best recovery as revealed by Pn, Gs, F(v)/F(m) and . Its ability to sustain chilling stress seemed related in part to the fast closure of stomata, suggesting an 'avoidance strategy' for this clone. IRCA707, GT1 and YUNYAN77-4 were also tolerant to the cold treatment as only a few leaf injuries were observed. However, YUNYAN77-4 showed a particular behaviour with a large stomata opening during the first hour of chilling, some photosynthetic activity after 96?h at 10?°C, but the slowest recovery in Pn. The greatest cell or leaf damage was observed on PB260, IRCA317, PR107 and PB217 clones, thus classified as sensitive to chilling. These clones showed the strongest decrease in Pn, F(v)/F(m) and and the slowest recovery for F(v)/F(m) and , indicating a high sensitivity of photosystem II to cold temperatures. Punctual increases of various enzymatic activities were observed for all clones during chilling kinetics. During recovery, the strongest increases in enzymatic activity were observed for the most tolerant clones, suggesting that efficient reactive oxygen species elimination is a crucial step for determining chilling tolerance in Hevea although the enzymes implicated varied from one tolerant clone to another. This study points out contrasted strategies of the Hevea clones in copping with chilling stress and recovery.     

Evaluation of Brazilian wild <Emphasis Type="Italic">Hevea</Emphasis> germplasm for cold tolerance: genetic variability in the early mature growth

Hevea brasiliensis is a commercially cultivated species for its natural rubber(NR) latex in South East Asian countries. To meet the ever-increasing demand, NR cultivation has been extended to non-traditional regions due to the limited scope of further expansion in traditional rubbergrowing areas in India. These areas are often confronted with various abiotic stresses, especially high and low temperatures, which cause reduction in plant growth, thereby increasing its uneconomical immaturity period. Eighteen wild Hevea accessions along with two modern clones RRII203 and PB 235 and two check clones RRIM 600 and Haiken 1 were evaluated in the early mature growth phase.The site was at Nagrakata, West Bengal, the sub-Himalayan cold-prone region of India. In Hevea, crop production is governed by two major factors, growth-vigor and production capacity. Growth-vigor is of special importance because the production of rubber is a process linked with the early growth of the plant, which results in early tappability and early economic gains. The genotypes exhibited highly significant clonal differences(P = 0.05) for all the growth traits. Tappability percentage in the seventh year, ranged from 0.33 %(AC 3074, AC 3075, AC 3293) to 89.67 %(RO 2727). The most vigorously growing accession(RO2727) reached tappabile girth early in the seventh year when the girth of plant ranged from 22.38 cm(AC 3293) to53.12 cm(RO 2727). The general mean was 43.32 cm, and the similar growth trend was exhibited by these accessions in the tenth year also. Annual girth increment(cm a-1) over3 years ranged from 1.81 cm(AC 3075) to 6.80 cm(RO2727). The mean winter girth increment(cm a-1) over4 years ranged from 0.13 cm(AC 3075) to 0.96 cm(RO2727) as compared to the check clone RRIM 600(1.11 cm)and Haiken 1(1.10 cm). Wide differences between the phenotypic coefficient of variation(50.29) and genotypic coefficient of variation(24.82) were observed for winter girth increment. Girth in the tenth year recorded the highest heritability(87 %). Girth was significantly correlated with the other growth traits. The top 30 % of the potential accessions showing high growth vigour and early tappability under cold stress were identified. These ecotypes/selections have high potential value for the development of coldtolerant clones for these regions and also in broadening the genetic base of the present-day cultivated rubber.     

Response of in vitro obtained oil palm and interspecific OxG hybrids to inoculation with Phytophthora palmivora

Bud rot (BR) disease caused by Phytophthora palmivora is the most devastating disease in oil palm cultivation in America. Oil palms that survived BR epidemics were found in areas highly devastated by the disease; these palms were introduced into Cenipalma's in vitro micropropagation (cloning programme). A severity scale was developed for in vitro palms from five ortets inoculated with two different P. palmivora isolates. Then, eight ortets of Elaeis guineensis and two ortets of the OxG interspecific hybrid were evaluated in two inoculation trials under chamber growth conditions. The clone performance response was consistent with that reported in the field for the corresponding ortets, and two contrasting ortets, one susceptible (ortet 57) and one resistant (ortet 34) were identified. We monitored and compared defence responses to P. palmivora in the contrasting ortets. An increase in reactive oxygen species (ROS) production after inoculation with the pathogen was observed, with higher accumulation of H₂O₂ in the resistant plants. Catalase (CAT) activity in resistant plants increased after inoculation with the pathogen from 24 hr post‐infection (hpi) and remained high during the observation time. In the susceptible ortets, there was a significant increase on catalase activity only at 48 hpi. Peroxidase (POS) activity increased in clones from both susceptible and resistant ortets, but the increase was much greater in the susceptible ones. Phenylalanine ammonia lyase activity increased in response to inoculation, and these increases were greater in clones of the susceptible ortet than in clones of the resistant ortet.     

The potential for increasing rubber production by matching tapping intensity to leaf area index

Understanding resource capture can help design appropriate species combinations, planting designs and management. Leaf area index (LAI) and its longevity are the most important factors defining dry matter production and thus growth and productivity. The ecophysiological modifications and yield of rubber (Hevea spp.) in an agroforestry system (AFS) with beans (Phaseolus vulgaris L.) were studied. The experiment was established in Southeast-Brazil, with three rubber cultivars: IAN 3087, RRIM 600 and RRIM 527. The AFS comprised double rows of rubber trees along with beans sown in autumn and winter seasons in 1999. There was about 50% higher rubber yield per tree in the AFS than the rubber monoculture. Trees within the AFS responded to higher solar radiation availability with higher LAI and total foliage area, allowing its greater interception. All three cultivars had higher LAI in the AFS than monoculture, reaching maximum values in the AFS between April and May of 3.17 for RRIM 527; 2.83 for RRIM 600 and 2.28 for IAN 3087. The maximum LAI values for monocrop rubber trees were: 2.65, 2.62 and 1.99, respectively, for each cultivar. Rubber production and LAI were positively correlated in both the AFS and monoculture but leaf fall of rubber trees in the AFS was delayed and total phytomass was larger. It is suggested that trees in the AFS were under exploited and could yield more without compromising their life cycle if the tapping system was intensified. This shows how knowledge of LAI can be used to manage tapping intensity in the field, leading to higher rubber yield.     

割面宝控制橡胶树树皮溃疡病扩展试验

割面宝是一种新型橡胶树割面保护剂。通过在橡胶品系RRIM60 0 ,2～ 3年生离体和活体材料上的试验 ,对橡胶割面条溃疡病 (病原Phytophthoracitrophthota)病斑扩展有显著的抑制作用 ,抑制能力和生产上使用的有效农药治疡灵相近 ,差异不显著     

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.     

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。     

Field survival and growth of clonal,micropropagated Eucalyptus marginata selected for resistance to Phytophthora cinnamomi

Clones of jarrah (Eucalyptus marginata), micropropagated from glasshouse-grown seedlings selected for resistance or susceptibility to Phytophthora cinnamomi, were planted in a former bauxite mine-site in the jarrah forest and inoculated with P. cinnamomi. Mortality after 13 years in resistant clones was 0–30%, while that of susceptible clones was 40–100%. Mean heights of resistant clones after 13 years were 7.8–13.6 m, while heights of surviving susceptible clones were 0.9–6.7 m. The resistance character of the seedling ortets was transmitted consistently to the clones. The field mortality of clones of some rare, apparently resistant seedlings selected from susceptible half-sib families was low after 1 year, but approached that of the susceptible clones after 2 years. The results show that Phytophthora-resistant jarrah ortets can be selected using stem-inoculation of glasshouse-grown seedlings; the resistance of the resulting clones has been validated in the field in an inoculation trial.     

Changes in host chitinase isoforms in relation to wounding and colonization by Heterobasidion annosum: early and strong defense response in 33-year-old resistant Norway spruce clone

We studied the defense reactions of 33-year-old susceptible and resistant clones of Norway spruce (Picea abies (L.) Karst.) to the major root-rot fungus Heterobasidion annosum (Fr.) Bref. and determined if tissue cultures can be used as a model system for studying defense responses of mature trees at the molecular level. Quantitative PCR analysis of genomic DNA obtained from samples taken at different times along the lesion length in living bark indicated that the fungus was present in higher amounts and extended further into the host tissue in the susceptible clone than in the resistant clone. In protein extracts from the same lesion samples, there were differences in temporal and spatial changes in host chitinase isoform profiles between the resistant and susceptible clones. Host chitinase isoforms with pI values approximately 4.8, 4.4 and 3.7 increased more during the first 7 days after wounding and inoculation and extended further along the lesion length in the resistant clone than in the susceptible clone. These results suggest that the time from wounding and infection to induction of defense-related expression is shorter in the resistant clone indicating a more efficient host defense response than in the susceptible clone. Tissue cultures from the same clones were not resistant to H. annosum and showed no difference in the timing of the increase in chitinase isoforms in response to the pathogen. However, tissue cultures from both clones showed an increase in chitinase isoforms within 6 to 24 h past inoculation, indicating that increased chitinase expression in response to the pathogen is part of a general defense response common to both mature clones and tissue cultures.