The physical, chemical and mineralogical properties of the soils under rubber (Hevea brasiliensis) from the south western region of Peninsular India were studied and classified as per soil tax­onomy. The texture of the soils varied from sandy clay loam at the surface to clay in the lower solum. The soils in general were deep and profiles exhibited distinct A and Bt horizon indicating clay migration by illuviation. Bulk density showed a decrease with depth while porosity showed an increase. Soils had dominantly kaolinitic mineralogy with lesser amounts of iron oxide, gibbsite along with illite in degraded forms, which warrants attention with respect to potassium nutri­tion. The soils were acidic in reaction (pH 4.5-5.9) and L1pH values suggested that these were near. to zero point charge. The mean profile cation exchange capacity (CEC) values ranged from 4.1 to 11.7 cmol (p+) per kg soiL The organic matter content was high and it decreased with depth. The C/N ratio of the surface layer was around 10 suggesting that the organic matter was highly decomposed. The soil analysis for total and available nutrients revealed that they were extremely deficient in available phosphorus and low in available potassium. The available magnesium content was found to be high in some regions calling for rescheduling of K fertilizer recommen­dation. The soils were classified into three great groups, Kanhaplustults, Kandiustults and Kandihumults

The effluent treatment process used in rubber processing industries in Vietnam comprises pond, aerated lagoon, OAF, UASB, chemical precipitation, SBR, septic tank, conventional activated sludge and trickling filter. The treated effluent was found to have COD, BOD and ammoniacal nitrogen on an average of 876, 322 and 50 mg/l respectively. These effluent qualities do not comply with Vietnam industrial wastewater standards. Besides, malodour and ground water contamination are the other principal drawbacks. Improvements in the system are therefore, imperative.

Stress relaxation measurements in tension were made on aluminium powder filled natural rub­ber vulcanizates and the results were compared with those containing high abrasion furnace black, general purpose furnace black, acetylene black, china clay and precipitated silica. A two ­stage relaxation mechanism was observed in all cases except for the unfilled stock. The rate of relaxation increased with aluminium powder loading. The relaxation process was also found to be influenced by the presence of bonding agents such as hexamethylene tetramine-resorcinol system, bis [3-(triethoxy silyl) propyl] tetra sulphide, cobalt naphthenate and toluene diisocyanate. Composites containing bonding agents showed a slower rate of relaxation and higher cross-over time than those without bonding agents. This is due to the improved adhesion of aluminium powder with natural rubber in presence of bonding agents, which was confirmed by the equilib­rium swelling values and scanning electron photomicrographs.

Two clone evaluation trials with five clones each were planted during 1987 and 1988 to study the adaptability of Hevea brasiliensis clones in the Coastal Karnataka region. Growth of the clones was monitored by measuring girth initially at annual intervals and later at quarterly intervals. The growth was compared by means of absolute girth and girth increment values. Clones PB 235 and RRII 118 were found to be the more vigorous. A quadratic trend was fitted for annual aver­age girth as a function of age. Clones showed non-significant variation for girth increment. The growth in terms of girth increment (GI) was fitted as a power function of age (X). Since all the clones irrespective of the trials showed similar growth trend, a general equation, GI = 616.012     X^-1.8982 was fitted. Comparison of quarterly and half-yearly girth increment has shown that, growth was maximum during the rainy season (April-October). There was no definite pattern of contri­bution so far as individual quarters were concerned.

A staining procedure using 1 per cent Oil red O prepared in 90 per cent isopropyl alcohol was tested for its ability to stain laticifers in H. brasiliensis. Laticifers were stained a deep-red maroon with Oil red O, whereas a red colour was developed with Sudan III and Sudan IV. Oil red O took the least time for stain preparation and gave maximum stainability when compared to Sudan III/ IV preparations. It was found to be a suitable stain for laticifers of Hevea brasiliensis. 

Abiotic stress induced over-expression of superoxide dismutase (SOD), catalase and peroxidase enzymes were studied in the transgenic embryogenic calli of Hevea brasiliensis, clone RRII 105. Two month old calli were transformed using Agrobacterium tumefaciens harbouring the binary vector containing neomycin phosphotransferase (npt-II) for kanamycin resistance as the marker gene for selection, β-glucuronidase (GUS) as the reporter gene and the sequence coding for SOD enzyme under the control of FMV 34.S promoter. The transformed calli were proliferated in modi­fied Murashige and Skoog medium fortified with hormones 2,4-D (4.5 µM), BA (2.2 µM) and NAA (1.1 µM). Over-expression of SOD, peroxidase and catalase enzymes in response to abiotic stresses like water stress, osmotic stress and different light regimes in transgenic embryogenic callus cultures were determined. Water stress was induced by the addition of different concentra­tions (0.2-1.0%) of phytagel and osmotic stress using polyethylene glycol (PEG), mannitol and sorbitol (2-10%) in the culture medium. More than 50% over-expression of SOD was observed when 0.4% phytagel was added to the medium and 40% over-expression was obtained when the culture medium was supplemented with 4.0% PEG. Catalase and peroxidase were also over­expressed correspondingly.