Latex Harvesting Technologies Adapted to Hevea brasiliensis Muell Clones GT 1; RRIC 100 and BPM 24 Arg. (Euphorbiaceae) belonging to the Moderate Metabolism Class in the Socio-economic Context of Côte d'Ivoire

Improving the productivity of rubber trees has always been a major concern for rubber farmers. The majority of growers opt for overexploitation of the trees. This disturbs the physiological balance of the rubber trees, which leads to the recrudescence of tapping panel dryness and rather to a drop in production. To solve this problem, the present study proposes to define a latex harvesting technology (or technologies) for the moderate metabolism clone class that will allow the improvement of plantation yield and the increase of the economic life of the trees. To achieve this, the GT 1, RRIC 100 and BPM 24 clones of the moderate metabolism class were used as plant material. The results showed that the reduction in tapping frequency had no negative effect on the vegetative state of the trees. This reduction was compensated by a high number of annual stimulations, which resulted in high dry rubber production. Analysis of dry rubber production, radial rubber growth and tapping panel dryness rate indicates that the moderate metabolic class clones performed better with the latex harvesting technologies S/2 d3 6d/7 ET2.5% Pa1(1) 6/y; S/2 d4 6d/7 ET2.5% Pa1(1) 6/y and S/2 d5 6d/7 ET2.5% Pa1(1) 1.

Genome-wide identification of lncRNAs, miRNAs, mRNAs, and their regulatory networks involved in tapping panel dryness in rubber tree (Hevea brasiliensis)

Noncoding RNAs (ncRNAs) play pivotal roles in various biological processes in plants. However, the role of ncRNAs in tapping panel dryness (TPD) of rubber tree (Hevea brasiliensis) is largely unknown. Here, the whole transcriptomes of bark tissues from healthy and TPD trees were performed to identify differentially expressed long ncRNAs (DELs), microRNAs/miRNA (DEMs), genes (DEGs), and their regulatory networks involved in TPD. A total of 263 DELs, 174 DEMs, and 1,574 DEGs were identified in the bark of TPD tree compared with that of healthy tree. KEGG analysis revealed that most of the DEGs and targets of DELs and DEMs were mainly enriched in metabolic pathways, biosynthesis of secondary metabolites, and plant hormone signal transduction. Additionally, the majority of DEGs and DELs related to rubber biosynthesis were down-regulated in TPD trees. Furthermore, 98 DEGs and 44 DELs were targeted by 54 DEMs, 190 DEGs were identified as putative targets of 56 DELs, and two and 44 DELs were predicted as precursors and endogenous target mimics (eTMs) of two and six DEMs, respectively. Based on these, the DEL-DEM-DEG regulatory network involved in TPD was constructed, and 13 hub DELs, three hub DEMs and two hub DEGs were identified. The results provide novel insights into the regulatory roles of ncRNAs underlying TPD and lay a foundation for future functional characterization of lncRNAs, miRNAs, and genes involved in TPD in rubber tree.

Relationship between the Intensity of Latex Harvesting and the Tapping Panel Dryness Expression of Clone GT 1 of Hevea brasiliensis Muell Arg in South-East Côte d'Ivoire

Tapping panel dryness is an important limiting factor in rubber productivity of Hevea brasiliensis. In order to assess the sensitivity to this syndrome, the effect of two intensive latex harvesting technologies on moderately metabolized GT1 clone, has been studied in the South-Eastern region of Côte d'Ivoire. The rubber trees were planted according to the experimental mono-tree device, "One tree one plot design" a tree constituting a repetition, and 31 trees per treatment, selected on circumference and health status criteria. The parameters measured were rubber production, circumference increase, physiological profile and tapping panel dryness sensitivity. The results showed that induction of tapping panel dryness in latex harvesting system, S/2 d/3 6d/7 ET 10 % Pa 1 (1) 1/ w) was significantly low (0.18 ± 0,22 %) than that of the control (S d/1 6d/7 unstimulated, 1.43 ± 1.45 %). Productivity of this particular system was also good (62 ± 16.32 g.a-1.s-1) and it especially has less stress that can cause physiological fatigue, or even the notch dry. Otherwise, Rubber production, radial vegetative growth, physiological parameters of the latex and the tapping panel dryness rate were influenced by the two treatments applied to GT 1. In addition, the medium and high sucrose contents (16.5 ± 3.01%) and thiol group (0.51 ± 0.13 mmol.l-1) of the latex in the treatment (S/2 d/3 6d/7 ET 10% Pa 1 (1) 1 / w), were instrumental in the response to this stimulation. The sensitivity to the tapping panel dryness is in very close linear relation with the harvest intensity of the latex to which the GT 1 clone has been subjected. These results corroborate and confirm the moderate sensitivity to the tapping panel dryness of GT 1 clone.

Quantitative Assessment of the Agro-physiological Advantages of Upward Tapping in Relation to the Downward Tapping of the GT 1 and PB 260 Rubber Clones [Hevea brasiliensis, Muell. arg. (Euphorbiaceae)] in Southwest Côte d'Ivoire

The downward tapping on virgin bark of the lower panel (BO) is immediately followed by the upward tapping on virgin bark of the upper panel (HO), consecutively. To determine the agro-physiological advantages of one tapping over another, a study of the downward and upward tapping of the GT 1 and PB 260 clones of Hevea brasiliensis was carried out in southwestern Côte d'Ivoire. For this purpose, the rubber trees were tapped in a downward half-spiral (S/2) at the opening for nine consecutive years, followed by upward quarter-spiral tapping (S/4U) for four consecutive years. The agronomic parameters (rubber production and vegetative growth), tapping panel dryness and the latex micro-diagnosis, were evaluated. For GT 1 clone, the transition from the downward tapping panels to the upward tapping panels resulted rubber productivity gain of 35%. Meanwhile for PB 260, rubber productivity gain was 37%. Regardless of the clone and tapping direction, the higher the rubber productivity of a respective tapping panel, the lower the isodiametric growth of the tree trunk was recorded. Latex harvesting systems, and clone’s combination, did not influence the tapping panel dryness or the physiological profile of the trees. Finally, it should be concluded that upward tapping is more productive than downward tapping, but the quantification of the gains in this rubber production depends on the clone.

Effect of high-frequency tapping system on latex yield, tapping panel dryness, and biochemistry of young hillside tapping rubber

The objective of this study was to examine the effect of high-frequency tapping system (1/3S 3d/4) on latex yield, biochemistry and its impact on the Tapping Panel Dryness (TPD) of young RRIM600 hillside tapping rubber. The experiment was conducted at three different hillside rubber plantations (NM 1 - 3) at Na-Mom district, Song Khla province, Thailand. Eight-year-old rubber RRIM 600 clones was used in the experiment starting from 2008 until 2009. The rubber trees were investigated for latex yield production, bark consumption, and TPD. In addition, latex diagnosis (sucrose, inorganic phosphorus (Pi), and thiol levels) was measured. The results demonstrated that high-frequency tapping system positively affected the rubber latex yield formation. However, site-specific condition of rubber plantation altered latex yield production. NM 3 provided the highest latex yield (fresh and dry weight) as compared to other plantations. Tapping frequency was highly correlated to latex yield (fresh and dry weights) in all investigated rubber plantations (R2 > 0.75). Using high-frequency tapping system increased bark consumption and stimulated TPD. Moreover, results of latex diagnosis (sucrose, Pi, and thiol levels) showed relatively unhealthy rubber tree as impacted by high-frequency tapping system. Therefore, the farmer should consider it for better decision-making for tapping system application.

Role of Cultivation Technology and Planting Patterns of Farmer Choice for Improving Smallholding Rubber Productivity

<p>Smallholding rubber productivity in Indonesia is still relatively low due to low cultivation technology adoption. The characteristics of smallholder plantations, with limited land tenure and capital, require a specific approach compared to large plantations. This article is aimed to inform rubber cultivation innovations to improve smallholder rubber productivity. Land conservation can increase the opportunity for developing rubber in sub-optimal environments such as peatlands, tides and high-elevated areas. Plant breeding activities in Indonesia have resulted IRR superior clones series with high yield potential (more than 1,500 kg/ha/yr), vigorous growth, and resistance to main diseases. Modification of planting space can increase land productivity and alternative income for farmers during immature period. To obtain the high yield, the clonal typology harvesting system supported by latex diagnosis can optimize the potential of clones and prevent tapping panel dryness (TPD). To increase technology adoption at the farm level, the role of extension workers, farmer groups, and support from the government is required.</p><p>Keywords: Rubber, farmers, technology, productivity</p><p> </p><p><strong>Abstrak</strong></p><p><strong>PERAN TEKNOLOGI BUDI DAYA DAN POLA TANAM PILIHAN PETANI DALAM MENINGKATKAN PRODUKTIVITAS KARET RAKYAT </strong></p><p>Produktivitas tanaman karet rakyat di Indonesia masih tergolong rendah, terutama disebabkan oleh adopsi teknologi budi daya belum optimal. Karakteristik perkebunan karet rakyat, terutama penguasaan lahan dan modal yang terbatas, memerlukan pendekatan spesifik dibanding perkebunan besar. Tulisan ini menginformasikan inovasi teknologi budidaya karet yang dapat meningkatkan produktivitas karet rakyat. Konservasi lahan dapat meningkatkan potensi pengembangan tanaman karet di lahan suboptimal seperti lahan gambut, pasang surut, dan daerah berelevasi tinggi. Pemuliaan tanaman di Indonesia telah menghasilkan klonklon unggul seri IRR dengan potensi hasil tinggi (rata-rata di atas 1.500 kg/ha/th), pertumbuhan jagur, dan tahan terhadap penyakit. Modifikasi pola tanam dapat meningkatkan produktivitas lahan dan sumber pendapatan petani selama tanaman belum menghasilkan (TBM). Untuk mendapatkan produksi yang tinggi dan berkelanjutan, sistem pemanenan lateks tipologi klon yang didukung oleh diagnosis lateks dapat mengoptimalkan potensi klon dan mencegah kering alur sadap (KAS). Untuk meningkatkan adopsi teknologi di tingkat petani diperlukan dukungan penyuluh, kelompok tani, dan pemerintah.</p><p>Kata kunci: Karet, petani, teknologi, produktivitas.</p>

Effect of low-frequency tapping systems (d5; d6) on latex yield, labor productivity and latex physiological parameters on RRIV 106 clone

The tapping labor shortage has been identified as a major issue for natural rubber companies in Vietnam. This study aimed to determine a suitable tapping system to adapt to the labor shortage. The experiment was conducted on RRIV 106 clone at Dong Phu rubber company, Binh Phuoc province, Vietnam in two the tapping years 2018 and 2019. The results showed that the treatments of low-frequency tapping systems (d5, d6) increased individual yield per tree per tapping (g/t/t) compared with that of d4. The g/t/t of treatments d5 and d6 with latex stimulant (ET 2.5%) applied by 6 to 10 times per year (d5, ET.6/y; d5, ET.8/y; d6, ET.8/y; d6, ET.10/y) was 23; 27; 45 and 47% higher than that of the control (d4, ET.4/y), respectively. Labor productivity (kg/task/day) of low-frequency tapping systems increased similarly to g/t/t. The tapper requirements of low tapping frequency (d5 and d6) were 20% and 33% lower than that of d4, respectively. Land productivity per year (kg/ha/year) of low-frequency tapping systems (d5 and d6) was equivalent (98 to 101%) as compared with that of the control. The effects of tapping systems on latex physiological parameters, tapping panel dryness rate (TPD), and dry rubber content (DRC, %) were not significantly different.