Indian natural rubber (NR) plantation sector supports an industry that is vital to the nation’s industrial and economic growth.  Sustained extension efforts supported by focused research and development by the Rubber Board in the past more than 60 years helped establish a robust NR production base in the country, characterised by a steady expansion in area under cultivation and increase in productivity and total production. This helped India achieve near self-sufficiency in NR production until 2010. The rubber products manufacturing industry and earnings from export of value added rubber products registered a robust growth over the years. As the Indian economy is expected to maintain its buoyancy in growth, it is estimated that by 2030 the country would require about 20 lakh tonnes of NR per year.  Present production is in the range of 6 to 7 lakh tons per year, although there exists the potential to produce about 10 lakh tons a year. Between now and 2030, the country should double its domestic NR production potential to become self-reliant and avoid excessive dependence on import of this critical and strategic industrial raw material. This calls for a mission mode approach with sufficient public and private investments to expand NR cultivation to more areas, replant old and senile holdings and increase productivity of existing holdings for which a road map is presented.

Progenies of the 1986 hybridisation programme comprising 147 hybrid clones evolved by crossing 17 parents in 33 cross combinations were evaluated in four small scale trials at the Central Experiment Station of the Rubber Research Institute of India. The variability for yield, yield components, timber and growth traits was studied over the immaturity period and the early mature phase.  Heterosis of the hybrid clones for yield, girth and bole volume was estimated.  The family-wise performance for important traits as well as the clonal performances compared to the 15 parental clones were studied. Estimates of heterosis for yield ranged from 2.4 to 91.5 per cent, girth from 2.3 to 23.8 per cent and bole volume from 5.3 to 94.7 per cent. The family RRII 105 x RRII 118 produced the largest number of heterotic hybrids for rubber yield and girth while the family PB 5/51 x RRII 208 gave large number of heterotic hybrids for bole volume, girth and yield. The study identified six clones viz. 86/111, 86/117, 86/122, 86/428, 86/613 and 86/597 as the top most latex yielders and seven clones viz. 86/59, 86/468,  86/64, 86/597, 86/522, 86/61 and 86/428 as the top most timber yielders while clones 86/111, 86/428, 86/597, 86/64, 86/599, 86/99, 86/787, 86/59 and 86/79 were latex timber clones in the order of superiority in performance. The present study also confirms the superiority of clones RRII 203, PB 235 and RRII 118 for rubber yield and RRIC 52, RRII 203 and RRII 118 in terms of rubber yield, girth and timber volume.

Hevea brasiliensis is the only commercial source of natural rubber in Cameroon and its production can be severely limited by diseases such as leaf blight. The disease is mostly observed in smallholder rubber fields in South West Cameroon. For this study, leaf samples were collected from infected plants.  The pathogen was then isolated and identified as Pestalotiopsis microspora following the cultural and morphological characterisation of colonies developed from single spore isolates. Culture media, period of incubation, temperature and pH affected the mycelial growth of P. microspora. Inoculation on detached leaflets revealed the pathogenic capacity of this fungus. Re-isolation of the pathogen from the symptoms produced confirmed Koch’s postulates.   Molecular sequence analysis of the internal transcribed spacer (ITS) region 1 and 2 including 5.8S rDNA (ITS-5.8S-ITS2) confirmed the morphological identification. P. microspora was therefore identified as the causative agent of the leaf blight on rubber in South West Cameroon.

The effects of some fungicides were tested in vitro on mycelial growth of P. microspora. Banko plus (Chlorothalonil 550 g L-1  + Carbendazim 100 g L-1), Penncoz (Mancozeb 800 g kg-1) and Metalm 72 WP (Cuprous oxide 600 g kg-1  + Metalaxyl 120 g kg-1) tested at different concentrations revealed inhibitory activity in vitro. Among these fungicides, a marked efficiency of Chlorothalonil + Carbendazim was observed, though the inhibition of mycelial growth was more effective with Cuprous oxide + Metalaxyl at rates: 100,

75 and 50 per cent only.

A field experiment was conducted during 2009-2015 at Taranagar, West district of Tripura to study the effect of integrated nutrient management practices on growth of young natural rubber plants (NR) and on soil chemical properties. Growth of NR (clone RRIM 600) was compared among the treatments comprising an absolute control, bio-inoculant  alone, standard dose of chemical fertilizers and 25, 50, 75 and 100 per cent of the standard recommendation of N and P fertilizers in combination with bio-inoculants (BI). Though no significant improvement in girth was recorded during the initial two years of planting, increase in plant height was observed with the treatments 50 and 75 per cent of N and P in combination with bio-inoculants. Significant increase in girth was recorded from 3rd year onwards with the combined application of BI along with 50 or 75 per cent of N and P and the growth improvement was on par among the two levels. Application of BI alone was not sufficient to meet the nutrient demand of young rubber plants. A combination of 50 per cent of the standard recommendation of N and P together with the recommended dose of K and BI was effective in improving the growth of plants and improving the soil fertility with the added advantage of cost saving through the reduction of  N and P fertilizer by 50 per cent of the recommended dose.

A clonal nursery evaluation incorporating 20 clones including five hybrids and 15 ortets selected from diverse locations was laid out in Central Kerala region along with three check clones viz. RRII 105, RRII 414 and RRII 430. The selections were from Kanyakumari (traditional region), Guwahati (non-traditional region) and Wayanad (a high altitude region within the traditional belt). The hybrids from Kanyakumari performed better than the ortets from the region. Par 18 was the best performer with the highest test tap yield of 17 g t-1 t-1 and highest girth of 45.8 cm in the 6th year of planting. Three other hybrids from the region Par 10, Par 9 and Par 11 also showed high test tap yield comparable to RRII 414 and RRII 430, among which Par 10 recorded superior secondary traits in terms of girth and latex vessel rows (LVR).  Two ortets from Guwahati viz. RRSG 9 and RRSG 4 performed significantly superior to RRII 105 and on par with the modern check clones for growth and test tap yield. One ortet from Wayanad (P 270) recorded test tap yield on par with RRII 105 and exhibited high growth vigour and LVR distribution comparable to RRII 414 and RRII 430.  Six clones were identified for further evaluation based on test tap yield, girth and bark characters. RRSG 9 showed good response to stimulation. The performance of specifically adapted clones under ideal climatic conditions is discussed in the light of early selection in Hevea breeding.

The present study was taken up in Mayurbhanj district in Odisha where the Rubber Board, in association with the Government of Odisha, has implemented Rubber Block Plantation Projects for the socio- economically marginalized scheduled tribes.  The study found that the average annual household income of the respondent households with income from rubber was 188 per cent higher than that of households without income from rubber.  The average expenditure of households for personal conveyance, education and healthcare with income from rubber was 879, 491 and 481 per cent, respectively higher than their counterparts without income from rubber. A transformation was noticed in the type of houses constructed from the traditional mud huts to pucca houses having modern amenities to enhance the standard of living, as income from rubber started to flow in.  It is highly encouraging that the tribal households with income from rubber were investing the additional income earned from rubber in both physical and human capital. This can lay the foundation for a discernible change in the socio-economic status of the tribal communities and overall development of the region in the future.