This paper examines the constraints in the growth and capacity utilisation of the Technically Specified Rubber (TSR) processing industry in India. The study was based on a census of 51 TSR processing units, conducted across different sectors covering the five-year period from 2001-02 to 2005-06. TSR constituted less than 12 per cent of the total production of NR and the capacity utilisation was only 54 per cent during the year 2005-06. Less demand and margin, increasing cost of processing, processing based on the systems of" advance sales order" or" contract" triggered by market and price uncertainties, the position of processors as price takers in both the input and output markets etc. were the major factors responsible for the poor growth and low capacity utilisation of the industry. As a result, the unit cost across the industry, sectors and size classes, does not reveal a significant inverse relationship with the scale of operation and production. The processing units were found to be surviving with context - specific managerial practices. 

Somatic embryogenesis and plant regeneration have been achieved from leaf explants of the clone RRII 105 of Hevea brasiliensis. The embryogenic competence of callus induced from leaf explants of the same developmental stage taken from three different sources such as plantlets regenerated through somatic embryogenesis, budded plants grown in polybags and mature budded trees of the clone RRlI 105 were examined. Callus induction was obtained in modified MS medium containing 3.6 mM Ca(N0₃)₂·4H₂0 and 58 mM sucrose, supplemented with phytohormones 2,4-D (5.4 µM), BA (4.4 µM) and NAA (1.08 µM). Proliferated fresh callus was cultured for embryo induction in modified MS basal medium (2.11 mM Ca(N0₃)₂·4H₂0 and 2.0 mM KH₂P0₄) containing B5 vitamins, amino acids, 220 mM sucrose and phytohormones. Significant difference in rate and the time taken for embryogenic callus initiation was observed. The embryo induction medium containing 1.5 mM Ca(N0₃)₂·4H₂O along with 234 mM sucrose and solidified with (0.5%) phytagel was found to be optimal for embryogenic callus initiation. Embryogenic callus could be obtained only from callus induced from in vitro - somatic plants and polybag grown ­budded plants. Leaves from mature trees produced proliferating callus with little embryogenic competence. Embryo induction was simultaneous with embryogenic callus formation. After the induction of embryogenic callus, the rate of embryogenesis (60%) was similar in the proliferated embryogenic calli derived from leaves of both in vitro - derived somatic plants and glass house - grown budded plants. Embryo induction was obtained from proliferated embryogenic calli when the cultures were incubated in dark in modified MS basal medium (2.11 mM Ca(N0₃)₂·4H₂O and 2.0 mM KH₂P0₄) containing B5 vitamins, amino acids, organic supplements such as coconut water (5%), malt extract (50 mg/L), casein hydrolysate (300 mg/L), 175 mM sucrose and phytohormones BA (2.2 µM), GA3 (2.9 µM), Kin (1.25 µM), ABA (0.75 µM) and NAA (0.54 µM). Further embryo maturation and germination, carried out in media standardized earlier, were not affected by the source of explant. The effect of physiological juvenility of source plants and the influence of culture medium on embryogenic tissue initiation are discussed. 

The effect of interaction of root-knot nematode, Meloidogyne incognita and Bradyrhizobium sp. on growth, nodulation and nitrogen content in Pueraria phaseoloides, a cover crop grown in rubber plantations, was studied in a pot-culture experiment by inoculating different inoculum levels of M. incognita and Bradyrhizobium. Significant reduction in nodulation due to nematode infestation was observed. Maximum gall formation was recorded in plants inoculated with nematode alone. Simultaneous inoculation of Bradyrhizobium and nematode or nematode inoculation after 10 days of bacterial inoculation reduced the adverse effect of nematode. Plant growth was increased by 5 to 13 per cent over control. Nitrogen content in the root and shoot of P. phaseoloides was considerably reduced by nematode inoculation at different inoculum levels. However, pre-inoculation of Bradyrhizobium could increase nitrogen content of the plants.

The performance of 21 wild Hevea germplasm accessions was evaluated under biotic and abiotic stress conditions in the sub-Himalayan West Bengal at the Experimental Station of Rubber Research Institute of India, Nagrakata, Jalpaiguri, West Bengal. Assessment of these genotypes for yield and other secondary characters has indicated superiority of one accession, RO 5363, for yield. Both test tap yield for three years and normal tapping for two years showed stability. The rest of the germplasm accessions were inferior to the control clone RRIl 105. The accession RO 3172 was the most vigorous and had the highest girth, girth increment and number of tappable trees, though the yield was very low. The accession AC 1950, though showing fairly good yield, did not have good bark thickness and girth. Only three accessions showed tolerance to Oidium leaf disease, even after sulphur dusting. Selected genotypes might be used for future breeding programme. 

Natural rubber (cis-I, 4-polyisoprene) is synthesised as rubber particles suspended in latex, which constitutes the cytoplasm of latex producing cells. In the present study, sucrose, thiols and ionic composition of latex were correlated with flow characteristics and yield in seven Hevea clones. Thiols in the latex showed significant positive correlation with total latex volume and significant negative correlation with plugging index. Level of sucrose showed significant positive correlation with initial flow rate, total volume and yield of the latex. Among the ionic components, inorganic phosphorus (Pi) showed significant positive correlation with initial latex flow rate, total volume and yield while calcium (Ca) showed significant negative correlation with total volume and yield. The biochemical or inorganic ions present in the latex did not show any significant correlation with the physiological disorder namely tapping panel dryness (TPD). 

Experiments were conducted at two locations to assess the possibility of reducing the dosage of nitrogen applied as fertilizer in rubber seedling nurseries by supplying reduced doses of N as foliar urea spray, at the time of second round of N application. In both the locations, there was no response to the second dose of N, either as soil application Or as foliar spray, may be because the initial soil application of 250 kg N/ha was sufficient for the growth of rubber seedlings. The study points to the possibility of reducing the dosage of nitrogen in rubber seedling nurseries