Rubber  (Hevea brasiliensis) seeds were boiled and fermented with mixed culture and  pure culture of Bacillus licheniformis.   Following fermentation, saponification value  of the oil increased while its iodine  value,  acid  value  and  unsaponifiable matter  decreased; per  cent  yield  of total  lipid decreased while cyanide was undetectable. Percentage content of palmitic, stearic and oleic acids increased while  that of linoleic and  linolenic  acids decreased.  Behenic and  myristic  acids  were undetectable after  fermentation.  The  implication of these  fermentative  modifications for  the improvement of rubber  seed and  its oil for human consumption, agricultural and  industrial use are discussed.

Annual average price of natural rubber (NR) in India  during the 27 year  period  from 1968-69 to 1994-95 was analysed with the objectives of delineating the trend, identifying the different phases and direction of price movement and the contributing factors.   NR price in India did  not show any   significant pattern of consistent movement towards a particular direction in the long  run. Two broad phases (1968-69 to 1984-85 and 1985-86 to 1994-95) of   NR price movement were identified based on the observed trend. Wide but less frequent fluctuations and mild but frequent fluctuations were the characteristics of the first and  second  phases  respectively.  Among the different economic variables, viz., production, consumption, stock,   import and world price of NR, the production of NR was found  to be the most  significant variable influencing the price. Significant statistical relations were not discernible with import and world price.  Role of the non-quantifiable factors  in  price  determination could  not  be  ascertained; and   therefore, a  price forecasting based on the empirical modeling is less likely  to approximate  reality.

Morphological, physical   and chemical characteristics of the rubber   growing soils of south­western and south-eastern Nigeria  were studied. The terrain is flat to gently sloping. The soils are well  drained, deep  and  generally sandy with  clay content  ranging from 1.2 to 35 per cent, of low fertility  and  very  acid  (pH  4.2) to moderately acid  (pH 5.5).  Effective  cation  exchange capacity ranged between 1.56 and 8.93 cmol per kg soil. The organic carbon, total N and available P ranged from 1.1 to 42.7, 0.04 to 2.8 g per kg and  2.4 to 24.2 µg per g respectively. Soil structure varied from granular on the surface  to weak  moderate angular blocky  and  subangular blocky in the subsoils with  friable  to slightly  sticky  consistency. The soils were  found to be generally suitable for rubber  (Hevea brasiliensis) growth with  only slight  limitations of fertility and low clay content in most areas and a threatening erosion around Calabar.  The suitability of soils from different areas  was  in the  order  : Okhuo and  Benin  > Akwete > Odagwa > Calabar.

Blends  of natural rubber  (NR) and  1,2 polybutadiene (1,2 PBD) were  evaluated for  dynamic mechanical properties such  as storage modulus (E') and damping factor (tan d).  Computations have been made based  on mean  field theories  of Kerner  to predict  properties of the blends.   The discrete particle  model  predictions are found  to be moderately close to experimental results  in the case of 70/30 1,2 PBD/NR blend  assuming 1,2 PBD as matrix.   In the case of 50/50 blend having a  co-continuous morphology as  revealed   by SEM evaluation, predictions based   on polyaggregate model  are found  to be in agreement with experiment, with deviations in the range of -40°C to O°C which  lies between the   Tgs of the components.

Spatial  distribution of roots and  nutrients in the horizontal and vertical  planes  was assessed  in a five  year  old  rubber  plantation in Tripura, India.  Root concentration was seen in  the  top 18 cm layer.  Horizontally the roots were found upto 200 cm away from the plant base.  Nutrient concentrations were also higher in the top layer than in the lower layers.   There was a positive correlation between available phosphorus and fine root concentration suggesting influence of phosphorus in root development.

Factors responsible for low fruit set in open pollination and hand pollination were studied under the agro-climate of Kanyakumari District of Tamil Nadu. Oidium was noticed to cause severe damage to flowers and young fruits,  if not controlled properly.  The harmful effects of solar radiations could be minimised by providing an overhead partial shade.  Based on the stickiness of pollen and  floral biology, it is assumed that  pollination in Hevea could  be brought about  through an external agent  only.  The effectiveness of insect  repellent coils to keep away the  natural pollinating agents was  analysed with  a view  to use  them  as  an  alternative  for emasculation and  post  pollination plugging of flowers.    Low  pollination due to  insufficient transfer of  pollen  was  identified as  the  main  factor  responsible for  the  low  fruit  set  in open pollination.  The low fruit set, in spite  of adequate pollen transfer,  in controlled pollination is attributed to the damage caused to the panicles and  flowers during the process of emasculation, pollination and  post  pollination plugging.