A twelve-year study (2011-2022) was conducted at Taranagar Farm, Regional Research Station of the Rubber Research Institute of India, Agartala (23° 50' N, 91° 25' E), to evaluate the impact of planting pit sizes on root development and growth of Hevea brasiliensis. The experimental site, characterized by red loam and sandy loam soil with a depth exceeding one meter facilitated the investigation with three pit dimensions: 75 x 75 x 75 cm (standard LxWxD), 60 cm depth x 30 cm diameter (for polybag plants), and 45 cm depth x 20 cm diameter (for root trainer plants). Results indicated that pit size variation had no significant effect on the development of tap or lateral roots, nor on overall plant growth and yield. Economically, smaller pits reduced the planting cost by 59.6 per cent and 79.8 per cent for polybag and root trainer plants, respectively, compared to the standard pit size. The study concluded that using smaller pits is cost-effective without compromising on plant development, provided planting is timed with the onset of the monsoon season to allow adequate root establishment before winter. 

The livelihood of millions of families in major rubber-producing countries depends on natural rubber (NR) cultivation. Early 21st century’s high NR prices gave way to a sharp decline in the following decade, leading to abandonment of plantations, new planting and replanting of NR thereby reducing yield in many traditional NR producing nations. The declining enthusiasm in NR farming poses serious challenges for ensuring sustainable NR supply against growing demand. Institutional support play a pivotal role in sustaining NR production during price downturns. This paper examined trends and patterns in NR cultivation, production and consumption in major producing countries using time series data from 2001 to 2022. Additionally, it analyzed the support measures implemented during the period of price fall by the major NR producing countries. The study revealed diverse patterns and highlighted the need for robust support measures. Direct price support mechanisms, specifically those implemented in India, Malaysia and Thailand guaranteeing a minimum price for NR, have gained significant traction and endorsement. While these measures provide short-term relief to farmers, their long-term sustainability and financial feasibility warrant careful consideration. This study suggested that as global demand for NR rises, strategic interventions are imperative to navigate price volatility and ensure the resilience of NR cultivation.

Six clones viz. RRII 203, RRII 417, RRII 422, RRII 429, PB 235 and RRIM 600 were planted in 2009 at Mendipather, North Garo Hills, Meghalaya in block trials. All the clones except RRIM 600 attained tappability in seven years.  The trees were opened for tapping in 2016 under S/2 d2 6d/7 tapping system.  The highest tappability was recorded in RRII 429 (94%) followed by RRII 203 (88%), RRII 417 (86%), RRII 422 (83%), PB 235 (82%) and RRIM 600 (66%). Rubber yield over eight years showed the highest value for RRII 429 (52.9 g t-1 t-1) followed by RRII 422 (43.3 g t-1 t-1), RRII 417 (42.4 g t-1 t-1), PB 235 (37.2 g t-1 t-1), RRIM 600 (34.5 g t-1 t-1) and RRII 203 (34.2 g t-1 t-1). The estimated yield in terms of kilogram per hectare per year showed about 2500 kg for RRII 429 and over 2000 kg each for RRII 417 and RRII 422.  The estimated yield was over 1700 kg for PB 235 and about 1600 kg each for RRII 203 and RRIM 600. The highest timber volume was recorded in PB 235 (0.19 m3) followed by RRII 203 (0.18 m3), RRII 417 (0.16 m3), RRII 429 (0.14 m3), RRII 422 (0.12 m3) and RRIM 600 (0.09 m3). The tree biomass growth was estimated for the above ground biomass (AGB) of the clones. The highest value was recorded for RRII 203 (395 kg tree-1) and the lowest in RRIM 600 (288 kg tree-1). Carbon stock and carbon sequestration potential of the clones showed the highest value for RRII 203 followed by RRII 429, PB 235, RRII 417, RRII 422 and RRIM 600. In the present study RRII 429 and RRII 417 showed superior performance to RRIM 600 for all the growth and yield parameters studied. Clones RRII 203 and PB 235 showed superiority in terms of all growth parameters over RRIM 600 with comparable yield performance. 

The present study involved two seedling nursery evaluation of polycross progenies during 2008 and 2011 at the Ganolgre research farm under the Rubber Research Institute of India, Regional Research Station, Tura, Meghalaya to assess juvenile yield performance of polycross progenies.  In 2008 trial, the original plant population was 480 whereas it was 800 in 2011 trial.  Data on plant height (m) and girth (cm) were recorded one year after planting in the field.  Test tapping (g t-110t-1) of the progenies in both the trials were carried out two years after field planting.  In 2008 trial, the mean plant height was 2.8 m, girth was 8.7 cm and the juvenile yield was 4.02 g t-1 10t-1 with an yield range of 1.2-12.7 g t-110t-1, whereas in 2011 trial the plant height was 3.3 m, girth 8.7 cm and juvenile yield 2.3 g t-110t-1 with an yield range of 0.4-9.2 g t-110t-1. On the basis of test tap yield, top 15-20 per cent best performing seedlings (i.e. 41 selections) were selected in 2008 trial, while in 2011, 34 top yielding progenies were selected.

Fresh latex is generally used for preparation of ribbed smoked sheets (RSS) and are graded by visual grading as per ‘The Green Book’ specifications. Uniformity in quality is a major concern in India as sheets are mostly made in the small growers sector. This uniformity in quality can be achieved by adopting recommended processing practices through group processing centres (GPCs). To run a GPC in an economically successful manner, it is required to ensure an uninterrupted supply of latex throughout the year. For this, it is necessary to preserve latex by adding 0.25 to 1.00 per cent ammonia and this preserved field latex (PFL) can be used for making sheets during lean seasons. However, preserved field latex is not generally suitable for making sheets due to the immediate coagulation of the PFL at the point of contact of the acid with consequent formation of lumps of coagulum suspended in latex and the poor plasticity retention index (PRI) of the resulting rubber. This paper reports the results of treating the PFL with a proprietary chemical to maintain the PRI and a proprietary new method to prepare quality ribbed smoked sheet from the treated PFL. Both low ammonia and high ammonia preserved latex samples were stored for various periods under ambient conditions and were subjected to a chemical treatment. The samples were coagulated at regular intervals and raw rubber properties were studied. Dry rubber thus obtained was also compounded using a standard formulation and vulcanizate properties were evaluated. The study revealed that ribbed smoked sheet could be prepared from the treated PFL and good PRI values can be retained by suitable chemical treatment. It was found that the treatment did not affect the technological properties of rubber thus produced. The study showed that this method can be used for making ribbed smoked sheets from ammonia preserved field latex without adversely affecting the properties of natural rubber produced from it.