The history of rubber cultivation and breeding in India that led to the country becoming a secondary centre of diversity of Hevea brasiliensis is reviewed. The starting of rubber cultivation in India dates back to 1878. This makes the base populations of rubber in India close to the original shipment of seeds brought from Brazil to South East Asia. Hevea breeding in India, initiated in 1954 has evolved over the years in technique and outcome. The impact of genetic improvement in this strategically important commercial crop of India has brought the country to the forefront in rubber productivity worldwide. The well planned and systematic conventional crop improvement programmes played the single most pivotal role in this process of creating large breeding populations and harnessing desired recombinants. The RRII clones evolved by the Rubber Research Institute of India enjoy almost 100 per cent adoption across the traditional and non traditional rubber growing environments of the country; thanks to their local adaptability and high yields. Early tappability has been achieved in the latest hybrids of the RRII 400 series, some of which are promising in timber characteristics too. Location-specific breeding, especially for the non- traditional rubber growing regions is now being addressed in the most appropriate manner by utilizing sources of resistance to biotic and abiotic stress from domesticated as well as wild germplasm. A multidisciplinary approach to breeding with farmer participatory research is the strategy followed. Divergent crosses of Wickham clones x Amazonian wild accessions have helped realize higher estimates of heterosis compared to that in the hybrids from earlier crosses. Biotechnological interventions like molecular breeding and genetic transformation are employed for specific purposes to support crop improvement programmes. Achievements in this area include development of the first transgenic rubber plant and a large repository of molecular markers to enable marker assisted selection for further shortening the breeding cycle in this perennial species. This review chronicles the developments in genetic improvement research in India over the sixty years and provides future perspectives as well.

Reliable and up to date information on agricultural land and its changes are important for agriculture planning and management. Using remote sensing and GIS techniques, the present work aimed to find the spatio-temporal changes in natural rubber areas in Kanyakumari district of Tamil Nadu over a period of 27 years (1980-2007) and its distribution over soil management units (SMU) and slope. Landsat MSS and TM as well as IRS P6 LISS III data were used as satellite input data and ASTER digital elevation data for deriving slope information and ortho-rectification of satellite image. Satellite images were individually classified using K means clustering and labeled based on ground knowledge and ground control points (GCP) and compared with ground survey statistics. Rubber area along with slope and SMU map was brought into GIS and overlay analysis was done to understand the spatio-temporal changes in rubber area. Area under rubber in 1980 was 10693.3 ha and it increased to 15886.7 ha in 1992 and then to 20781.7 ha in 2007. About 8891.5 ha have been newly planted with rubber during 1980-2007. Majority of this newly planted area has come up in good to moderate soil with moderate to gentle slope. Present study also revealed that rubber area is skewed towards old plantations. The study assumes significance because so far no spatio-temporal rubber area mapping has been carried out in the study area. And also the study has thrown light on the skewed distribution of rubber area towards old age which will be useful for planning the replanting programmes. There is a need for integrated analysis of rubber area distribution with soil, topography and climate variation to assess their influence on rubber performance and to develop site specific management practices.

Rubber tree cultivation is facing a problem of availability of tapping labour. One way to overcome this constraint is the development of low intensity tapping system with use of yield stimulant (ethephon), reducing the need for tappers. Thus, a study was conducted in Côte d’Ivoire on low frequency tapping system compensated for, not by stimulation, but by an increase in the length of tapping cut. The standard tapping in S/4U d3 6d/7 was compared to the tapping in S/2U d6 6d/7 in clone GT 1. The results showed that although the tapping in S/2U d6 6d/7 causes losses of rubber yield by 13 and 25 per cent per tree and per hectare respectively, it generates gains in yield per tree and per tapping by 75 per cent and in net operational incomes by 3 to 4 per cent. Moreover, the tapping in S/2U d6 6d/7 has no significant impact on the physiological profile and the tapping panel dryness of trees. This technology can therefore be an alternative to the standard upward tapping in order to remedy the problem of availability of tappers and enable to palliate a deficit of 39 per cent of the needs for tappers without increasing the level of stimulation.

Corynespora cassiicola and Phytophthora meadii, the economically important pathogenic fungi of rubber (Hevea brasiliensis), were preserved with six different storage methods viz. continuous growth method, immersion in sterile distilled water, desiccation on filter paper, desiccation in soil, cryopreservation and lyophilization. Survival was evaluated 1, 3, 6, 9, 12, 18, 24, 36 and 48 months after storage. Immersion in sterile distilled water was found to be the best method for long term storage of both the test fungi with a revival rate of 71 and 62 per cent for C. cassiicola and P. meadii, respectively. C. cassiicola also survived well in cryopreservation and desiccation methods. It was significant to note that preservation through continuous culturing eroded the virulence of C. cassiicola over a period of time. In contrast, all other preservation methods sustained post-storage virulence of the pathogen, which is of high value for tissue based germplasm screening against Corynespora leaf disease. Immersion in sterile distilled water was the only method which could support the survival of abnormal leaf fall pathogen P. meadii and preserve its post-storage virulence. Therefore, this method could be used as efficient and cost effective preservation method for both the pathogens under study, without losing their pathogenicity.

One batch of 17 hybrids of Wickham (W) and Amazonian (A) parentage from six cross combinations were evaluated at the Central Experiment Station of the Rubber Research Institute of India. Yield of the clones in the BO-1 and BO-2 panels, combined yield from the two panels, summer yield, girth of the clones, biomass production and bole volume were evaluated. Heritability was moderate to high for both growth and yield parameters indicating scope for selection for the characters studied. Phenotypic variance and phenotypic coefficient of variation (PCV) showed values higher than the corresponding values for genotypic variance and genotypic coefficient of variation (GCV) for all the characters studied indicating the influence of environment on the characters. Secondary attributes like bole volume, biomass production and girth showed significant improvement in some of the hybrids (90/55, 90/109, 90/129 and 90/274) over the most popular and high yielding clone, RRII 105. Yield performance of these hybrids was on par with that of RRII 105. The hybrids which showed significantly improved bole volume and rubber yield comparable to RRII 105 may be designated as latex timber clones which could be utilized for further crop improvement programmes. Thus, without compromising on rubber yield it was possible to successfully develop W x A hybrids from divergent crosses in Hevea brasiliensis.

This study examines the price spread of sheet rubber in Tripura vis-à-vis small rubber growers organized under the Rubber Producers Societies (RPS) - Block Planting Scheme (BPS) network and unorganized growers. The study was based on primary data collected from 305 small rubber growers and 39 market functionaries. The net price of sheet rubber received by growers in the organized sector was about 90 per cent of the buyer’s price. Conversely, the growers’ share in the unorganized sector was found ranging from 83 to 86 per cent. The better marketing efficiency of growers organized under the RPS-BPS network over the unorganized growers has been reflected in terms of lower price-spread, higher efficiency index and increased growers’ share. The study suggests appropriate institutional interventions for more coverage of the small rubber growers under RPS.