Agrobacterium mediated genetic transformation is an effective tool for crop improvement in Hevea since stable integration of agronomically important genes can be brought about in substantially lesser time compared to the conventional breeding.  Transgenic Hevea plants have been regenerated successfully using standardized protocols developed earlier for genetic transformation.  Heat shock protein 31 gene from Saccharomyces cerevisiae (ScHsp31) was selected to engineer Hevea plants against the biotic and abiotic stresses. The heat shock protein Hsp31 routinely detoxifies Methylglyoxal (MG) which accumulates during abiotic and biotic stresses. Overexpression of ScHsp31 gene has resulted in enhanced stress tolerance of plants. This has been proved in tobacco plants which showed that transgenic expression of ScHsp31 gene confers protection against various cellular stresses.  Experiments were carried out for integration of ScHsp31 gene into Hevea callus for regenerating transgenics with enhanced stress tolerance. Genetic transformation was carried out in Hevea with pBIN-ScHsp31 gene construct in Agrobacterium strain LBA4404. The construct also harboured nptII gene for antibiotic selection. Friable and actively proliferating embryogenic calli obtained from the leaf cultures of clone RRII 105 were used for Agrobacterium infection. Transformation frequency of around 15 per cent was obtained when genetic transformation with pBIN-ScHsp31 gene was carried out in the earlier standardized medium. Kanamycin resistant calli were further proliferated and used for somatic embryogenesis.  Effect of antioxidants such as a-lipoic acid and glutathione on transformation efficiency was studied. Transformation efficiency could be enhanced to around 50 per cent by the addition of 50 mg  L-1 a­lipoic acid. Gene integration and expression in the transgenic calli lines was studied using semi-quantitative RT-PCR analysis where a 713 bp band was amplified with gene specific primers with no amplification in the untransformed calli. Somatic embryogenesis was also obtained from the transgenic and control calli. 

The study on socio-economic impact of natural rubber (NR) cultivation under the Block Planting Units (BPUs) in Tripura conducted in 2008 revealed (i) higher dependence on income from NR; (ii) lack of income diversification activities and (iii) low level of human capital formation in the rubber growing regions of Tripura, especially among the tribal rubber growers.  A revisit to the households surveyed in 2008 was done in 2019 to understand the changes in the socio-economic condition of rubber farmers in Tripura.  Though all the BPUs and Group Processing Units (GPUs) were revisited the present study could not locate all the 480 rubber farmers studied during the year 2008.  Data from 414 households were collected and analysed. An increase in (i) household income; (ii) size of the families; (iii) investment in alternative sources of income; (iv) availability of credit facilities; (v) borrowings of rubber farmers, etc. and decline in (i) area under NR and (ii) share of income from NR in total average household income were observed.  Sources of income of the rubber farmers were also diversified. As a result, NR farming was found to be a part-time activity for majority of the rubber farmers in Tripura. 

The impact of five cropping systems on total soil carbon (C) and related characters were evaluated and compared with that of a nearby forest. To assess the C sequestration potential of the systems, the distribution of the total C to different size fractions (2000-250 µm, 250-53 µm and < 53 µm) in the systems were estimated. Soil respiration rates of the systems were measured as an indication of microbial activity.  It was observed that total C in surface soils declined in all the cultivated systems compared to the forest system.  The distribution pattern of total C in physical size fractions were comparable in cropping systems but were different from that of the forest system. More of the total C were found in the bigger size fractions in forest system, while it was in the finer (< 53 µm) fraction in the case of the cropping systems. In rubber systems, more than 70 per cent of the total C was in the finer fraction indicating higher C sequestration potential of the systems. However, in terms of quantity of total C conserved, forest soil system conserved more C.  An ideal system would be one that can conserve more C with more of its allocation to the finer (< 53 µm) fraction. There exists possibility of converting rubber systems to more environmentally beneficial one if more under flora is allowed to grow during the immature phase along with restricted weeding and tillage practices.

The paper seeks to enquire the livelihood conditions of the tribal rubber growers of two major rubber growing districts of Assam viz.,Goalpara and Kokrajhar. Five livelihood assets or capital indices (physical, human, natural, financial and social) were used to reflect the livelihood conditions of these rubber growers of the chosen districts. Twenty three variables (called sub-components) were used to construct these five capital or asset indices. The five asset indices together constitute Sustainable Livelihood Indices (SLI) for each of the two districts in consideration. The SLI of the Goalpara tribal rubber growers was found to be higher than that of Kokrajhar growers indicating better overall socio-economic status of the growers of the former district. However, differences between the individual sub-components among the growers of the two districts were insignificant indicating almost similar livelihood assets status of the tribal rubber growers of the two districts. Some of the factors contributing to the existing livelihood conditions of the two selected districts were also identified in the paper for further policy implications.

The study was conducted in three rubber clone experimental trials to examine their timber volume potential in North East India. Clonal variability in timber volume was observed. Clone RRII 208 was the highest per tree timber yielder followed by RRIM 600 among the eight clones studied.  Girth class-wise variability in timber volume was the highest in lower girth class (below 70 cm) and a higher concentration of trees was observed in the girth class 70 to 90 cm. The relationship between girth and timber volume among the clones and within the clones was found to be positive. The power equation of girth (G) at 150 cm height and available green timber volume (V) for clone RRIM 600 was V = 0.000002 G2.6375. The average timber volume was 0.3 m3 tree-1. Average availability of timber was 88.2 m3 ha -1 at the age of 24 years for the clone RRIM 600. Potential rubber timber availability in NE India was estimated as 2.37 million cubic meters. The newly introduced clones, like RRII 429 recommended for planting in the region has been observed to have higher timber volume and may further contribute to availability of rubber wood timber in the region. 

Thirteen new Hevea clones along with three check clones viz. RRII 105, RRII 414 and RRII 430 were evaluated over a period of 12 years for growth, early yield, disease incidence and other desirable secondary traits in a large scale station trial as part of Participatory Clone Evaluation (PCE) programme (Phase 1) in Central Kerala, India. Among these, five clones viz., P 44, P 26, P 63, P 64 and P 70 were found to hold promise in terms of growth, dry rubber yield in the early phase and desirable component traits including disease tolerance compared to control clones. Clones developed through recombination and polycross breeding approaches performed equally well.  The high leaf retention in P 63 and P 70 even under the combined attack of abnormal leaf fall and circular leaf spot disease was noteworthy.  The performance of new cohort of clones in this central researcher trial will be compared with that of the satellite on farm trials to identify better region-wise adaptive clones for the future.