(hevea brasiliensis) clones - Rubber Board

Natural Rubber Research Volume 25 Number 1 2012 

CONTENTS 

RESEARCH PAPERS 

Juvenile-mature correlations and associations among rubber yield and 

yield attributes in Hevea brasiliensis 

Kavitha K. Mydin 1 

Changes in organic carbon and some soil properties under rubber 

(Hevea brasiliensis) plantation in sub-tropical Tripura 

Debasis Mandal, Tapan Kumar Pal, Sushil Kumar Dey and James Jacob 13 

Efficient screening of AFLP primer combinations for evaluating genetic 

diversity among cultivated rubber (Hevea brasiliensis) clones 

C. Bindu Roy, Minimol Ravindran and Thakurdas Saha 21 

Further evaluation and selection of 1981 IRRDB wild Hevea germplasm 

collection in India 

C.P. Reghu, M.A. Mercy and Radha Lakshmanan 31 

Influence of intercropping on growth of rubber (Hevea brasiliensis) 

and soil physico-chemical properties 

Elsie S. George, Phebe Joseph, M.D. Jessy, Kochuthresiamma Joseph 

and N. Usha Nair 39 

Methods to improve establishment success and growth of green budded stumps 

of Hevea in polybags 

V. C. Mercykutty and T. Gireesh 46 

Yield performance of clone RRII 105 under low frequency tapping in BO-2 

and BI-1 panels 

K. Karunaichamy, K.U. Thomas and R. Rajagopal 52 

Performance of certain exotic Hevea clones in Kanyakumari region 

T.A. Soman, M. Suryakumar, Kavitha K. Mydin and M.A. Nazeer 60 

Patron 

Sheela Thomas IAS 

Editor-in-Chief 

Dr. James Jacob 

Editors 

Dr. R. Krishnakumar 

Dr. Siby Varghese 

Secretary 

Dr. C. P. Reghu 

EDITORIAL BOARD 

Associate Editors 

Dr. Kochuthresiamma Joseph 

Dr. K. Karunaichamy 

Dr. Joshua Abraham 

Ms. K. Rekha 

Mr. M. J. Reju 

Ms. Phebe Joseph 

Editorial Committee 

Members 

Dr. D. Chaudhuri 

Dr. A. Thulaseedharan 

Dr. Rosamma Alex 

Treasurer 

CA. Zachariah Kurian

Polyhouse technology for production of healthy planting materials of rubber 

V.C. Mercykutty, Kavitha K. Mydin, Shammi Raj, C. Bindu Roy 

and P.M. Priyadarshan 68 

Detection and isolation of good quality DNA from the latex 

of Hevea brasiliensis 

A. Thulaseedharan, R.S. Sajeevan and A. Saleena 77 

Histochemical changes in embryogenic and non-embryogenic calli 

of Hevea brasiliensis 

P. Kumari Jayasree, C.P. Reghu, R.G. Kala and A. Thulaseedharan 86 

Trends in wage share in the context of labour shortage: 

The case of tapping wage share in rubber smallholdings sector in Kerala 

Binni Chandy and K. Tharian George 91 

Effect of storage on properties of natural rubber sheets in Tripura 

Joy Joseph, Leelamma Varghese, Sushil Kumar Dey and K.T. Thomas 100 

Distribution of protein-storing cells in the bark tissue of Hevea brasiliensis 

in response to tapping panel dryness and stimulation 

Vinoth Thomas, C.P. Reghu, V. Divya, P.K. Ambily and R. Krishnakumar 107 

Evaluation of polycross seedlings of prepotent Hevea clones – 

Potential for yield improvement and drought tolerance 

M.A. Mercy and Kavitha K. Mydin 115 

Figure on cover 

Protein-storing cells in the bark tissue 

See Vinoth et al., pages 107-114

Natural Rubber Research, 25(1): 1-12, 2012 

JUVENILE-MATURE CORRELATIONS 

AND ASSOCIATIONS AMONG 

RUBBER YIELD AND YIELD ATTRIBUTES IN 

HEVEA BRASILIENSIS 

Kavitha K. Mydin 

Rubber Research Institute of India, Kottayam-686 009, Kerala, India 

Received : 26 September 2011 Accepted : 15 December 2011 

Mydin, K.K. (2012). Juvenile-mature correlations and associations among rubber yield and yield attributes 

in Hevea brasiliensis. Natural Rubber Research, 25(1): 1-12. 

Early evaluation techniques to shorten the breeding cycle of Hevea have been investigated at large, but 

few have systematically studied the juvenile-mature correlations which are of paramount significance in 

deciding early selection criteria. A population of 150 polycross seedlings belonging to ten half-sib progenies 

was subjected to investigations on correlations among five juvenile traits and 18 mature traits. Juvenilemature 

correlations among these traits recorded over three years in the juvenile phase in a nursery and 

over 11 years in the subsequent mature phase of the 150 resultant clones planted in a compact family 

block design in the main field were studied. 

Juvenile girth, bark thickness and the number of laticifers emerged as important components showing 

positive association with yield determined by test tapping. Rubber yield in the first four years of tapping 

at maturity was significantly correlated with summer yield, girth, number of latex vessel rows in the 

soft bast and clear bole volume. Clear bole volume showed a higher positive correlation with girth 

than forking height, an indication that high girthing clones can be assumed to give high timber yields. 

The juvenile-mature correlations indicated test tap yield of two year old seedlings in the nursery to be 

the only juvenile parameter with a significant positive association with yield of the resultant clones at 

maturity in the main field. Girth, bark thickness and the number of latex vessel rows in the juvenile 

seedlings had no association with yield per se in the mature stage and hence, resorting to selection of 

seedlings based on juvenile vigour alone would lead to erroneous conclusions and loss of potential 

high yielders. 

Among the 29 clones with high yield at maturity 90% were from the high and moderately high test tap 

yield category while only 72% belonged to the moderate to high girth category. Only 7% of the low 

juvenile yielders gave high yield at maturity while 25% of the seedlings with low juvenile vigour gave 

high yield at maturity. The results suggest that nursery screening based on juvenile yield by test tapping 

remains the only reliable criterion in breeding for yield improvement. However, the relatively low 

strength of juvenile – mature correlation indicates that a combined and less stringent selection for traits 

such as juvenile yield, girth and the number of latex vessel rows in 2- 3 year old seedlings could give 

better recovery of high yielding clones at maturity. 

Keywords: Early evaluation, Girth, Hevea brasiliensis, Juvenile-mature correlations, Laticifers, Rubber yield, 

Timber 

Correspondence: Kavitha K. Mydin (Email: kavitha@rubberboard.org.in) 

1


CHANGES IN ORGANIC CARBON 

AND SOME SOIL PROPERTIES UNDER RUBBER 

(HEVEA BRASILIENSIS) PLANTATION IN 

SUB-TROPICAL TRIPURA 

Debasis Mandal, Tapan Kumar Pal, Sushil Kumar Dey and James Jacob* 

Regional Research Station, Rubber Research Institute of India, Agartala- 799006, Tripura, India 

* Rubber Research Institute of India, Kottayam-686009, Kerala, India 

INTRODUCTION 

In North East India, wide spread 

deforestation is a common practice mainly 

to meet the need for fuel wood, timber, 

forage etc. and thus destabilising the ecology 

of this region. The soils in this region are 

highly degenerated due to shifting 

cultivation (Datta et al., 2001) which is 

preceded by burning of organic debris in soil 

Received : 10 July 2011 Accepted : 24 October 2011 

Mandal, D., Pal, T.K., Dey, S.K. and Jacob, J. (2012). Changes in organic carbon and some soil properties 

under rubber (Hevea brasiliensis) plantation in sub-tropical Tripura. Natural Rubber Research, 25(1): 13-20. 

Changes in the status of soil organic carbon (SOC), available phosphorus (av. P), available potassium 

(av. K), pH and bulk density (BD) were studied in rubber plantations at an interval of two decades in 

Tripura. Composite soil samples collected at two depths viz. 0-30 cm (surface soil) and 30-60 cm (subsurface 

soil) during 1986 and 2006 from growers’ fields, were analyzed for the physico-chemical properties. 

The data showed that SOC content increased appreciably under rubber, particularly in the surface layer. It 

was observed that in a span of twenty years, SOC status in surface and sub-surface soil increased from 0.81 

to 0.96 and 0.66 to 0.73 per cent, respectively. The frequency distribution curve for SOC showed a positive 

shift indicating an increase of SOC under rubber soils over time, up to a depth of 60 cm. A total amount of 

10.2 mt C/ha was stored under rubber soils during twenty years of rubber cultivation and the rate of carbon 

assimilation in rubber soils was found to be 0.24 mt/ha/yr .The frequency distribution curve for av. K showed 

a building up at both the depths, whereas a decline in av. P status of the soil was observed during that 

period. No appreciable change in soil pH was recorded during this time and variation in BD of soils was 

inconclusive. The study revealed that cultivation of rubber in Jhum-lands of Tripura will be beneficial for 

restoring soil health. 

Keywords: Organic carbon, Rubber plantation, Soil properties, Tripura 

Correspondence: Debasis Mandal (Email: mandal.debashis@gmail.com) 

13 

floor, thereby reducing soil organic matter 

and microbial population. Planting rubber 

(Hevea brasiliensis) in these denuded soils not 

only gives an excellent cover, but also 

provides ample revenue to the people. 

Therefore, as a settlement of local tribes as 

well as to meet the increasing demand of 

natural rubber in the country, large-scale 

rubber plantating was initiated in North- 

Eastern region of India by many government


EFFICIENT SCREENING OF AFLP PRIMER 

COMBINATIONS FOR EVALUATING GENETIC 

DIVERSITY AMONG CULTIVATED RUBBER 

(HEVEA BRASILIENSIS) CLONES 

C. Bindu Roy, Minimol Ravindran and Thakurdas Saha 


Received : 20 October 2011 Accepted : 26 December 2011 

Roy, C.B., Ravindran, M. and Saha, T. (2012). Efficient screening of AFLP primer combinations for evaluating 

genetic diversity among cultivated rubber (Hevea brasiliensis) clones. Natural Rubber Research, 25(1): 21-30. 

Multilocus amplified fragment length polymorphism (AFLP) markers are used in genetic mapping, diversity 

analysis and genotyping. Success of the technique mainly depends on the identification of the primer 

combinations for selective amplification. In this study a simple method was demonstrated to identify the 

potential primer combinations using a mini polyacrylamide gel electrophoresis (PAGE) followed by silver 

staining. A modified silver staining protocol was developed to save time without compromising on the 

sensitivity. Further, the utility of the protocol in developing AFLP markers in rubber (Hevea brasiliensis) for 

assessment of genetic diversity among cultivated clones from different South East Asian rubber growing 

countries was demonstrated. 

Keywords: AFLP, Denaturing mini PAGE, Genetic diversity, Hevea brasiliensis, Silver staining 

INTRODUCTION 

Molecular markers are a pre-requisite 

for genome analysis of any organism. 

During the last two decades, several 

techniques viz. RFLP, RAPD, AFLP, 

microsatellite and SNP have been developed 

for polymorphism studies. AFLP marker 

system is widely used for genomic 

characterization, genome mapping and also 

to develop diagnostic markers that are 

linked to various agronomic traits. This 

technique is PCR-based and produces 

dominant markers having a high multiplex 

ratio because of the random placement of 

restriction sites between different genomes 

combined with nucleotide sequence 

Correspondence: Thakurdas Saha (Email: saha@rubberboard.org.in) 

21 

variability within a short stretch of DNA 

directly flanking these restriction sites (Vos 

et al., 1995). 

Although the AFLP technique is tedious 

and time consuming, this appeared to be the 

marker of choice for its multi-allelic 

properties. Success in developing AFLP 

markers depends on several important steps: 

(1) complete digestion of DNA samples with 

two restriction enzymes; (2) adaptor ligation 

of the restricted DNA; (3) pre-amplification 

of the adaptor ligated DNA sample using 

complementary oligonucleotides as primers; 

(4) selective amplification of the preamplified 

product using different primer 

combinations with a change at their 3´ ends


FURTHER EVALUATION AND SELECTION 

OF 1981 IRRDB WILD HEVEA 

GERMPLASM COLLECTION IN INDIA 

INTRODUCTION 

C.P. Reghu, M.A. Mercy and Radha Lakshmanan 

Rubber Research Institute of India, Kottayam – 686 009, Kerala, India 

Considering the need for broadening 

the existing narrow genetic base of natural 

Received : 26 May 2011 Accepted : 3 December 2011 

Reghu, C.P., Mercy, M.A. and Lakshmanan, R. (2012). Further evaluation and selection of 1981 IRRDB wild 

Hevea germplasm collection in India. Natural Rubber Research, 25(1): 31-38. 

A mature phase evaluation of selected wild accessions of Hevea brasiliensis from the 1981 IRRDB Brazilian 

wild germplasm collection established at the Rubber Research Institute of India was done on the basis of 

various agro-morphological traits such as growth, yield, bark anatomical characters and timber potential. 

These wild accessions represent three provenances of Brazil, viz. Acre, Rondonia, and Mato Grosso. Field 

experiments were conducted at the Regional Research Station of Rubber Research Institute of India at 

Padiyoor, in Northern Kerala. The popular clone, RRII 105 was used as control. 

The accessions showed significant variability for all the characters. In the year of opening, six out of eighty 

accessions were found superior to RRII 105 for girth and this trend continued for the subsequent five years 

under regular tapping. The accession MT 2233 was significantly superior to RRII 105 in bark thickness. 

Two Acre accessions (AC 635 and AC 166) had significantly higher number of latex vessel rows than that of 

RRII 105 and the number of latex vessel rows was on par with the control in 44 accessions. One Rondonian 

accession (RO 368) showed significant superiority for density of laticifers over RRII 105 and 11 accessions 

comprising two from Acre and nine from Mato Grosso provenances were on par with that of the check 

clone. Thirty three accessions had latex vessel diameter on par with that of RRII 105, indicating the scope 

for selection in the wild accessions for yield-related anatomical traits. Increased number of laticifer rows 

found in an accession might have contributed its high yield potential. 

Six accessions had significantly higher bole volume than that of RRII 105. Among these, two accessions 

with low dry rubber yield can be considered as potential timber yielding accessions and the remaining four 

accessions with high timber yield and comparatively medium latex yield can be considered for developing 

timber-latex clones. The wild accession AC 166, gave good yield and this was reconfirmed in further 

on-farm evaluation. The possibility of using the inherent genetic variability available in this wild population 

for future crop improvement programmes is discussed. 

Keywords: Bark anatomy, Brazilian germplasm, Dry rubber yield, Hevea brasiliensis, Timber yield, Wild 

accession 

Correspondence: Reghu, C.P. (Email: reghu@rubberboard.org.in) 

31 

rubber, Hevea brasiliensis, a joint effort in 

building up of fresh germplasm collection 

representing the centre of diversity in Brazil


INFLUENCE OF INTERCROPPING ON GROWTH OF 

RUBBER (HEVEA BRASILIENSIS) 

AND SOIL PHYSICO-CHEMICAL PROPERTIES 

Elsie S. George, Phebe Joseph, M.D. Jessy, Kochuthresiamma Joseph and N. Usha Nair 

INTRODUCTION 

Rubber Research Institute of India, Kottayam- 686009, Kerala, India 

In India 99% of the rubber plantation 

units are with smallholders and they cover 

more than about 90% of the total area and 

the mean holding size is around half a 

hectare per grower (Rubber Board, 2011). 

Since the immaturity period of rubber (Hevea 

brasiliensis) usually exceeds seven years, 

smallholders are forced to take up 

intercropping in order to get income during 

this period. Adoption of cropping system 

approach is indispensable to increase the 

Received : 16 May 2011 Accepted : 25 October 2011 

George, E.S., Joseph, P., Jessy, M.D., Joseph, K. and Nair, N.U. (2012). Influence of intercropping on growth 

of rubber (Hevea brasiliensis) and soil physico-chemical properties. Natural Rubber Research, 25(1): 39-45. 

The influence of intercropping on growth of rubber and soil physico-chemical properties was studied in a 

field experiment involving three intercropping systems viz. rubber/tapioca, rubber/banana and rubber/ 

pineapple in comparison with the standard rubber-cover crop system. Pineapple and cover crop were 

retained for 3-5 years and three crops of tapioca and banana were raised during this period. The girth of 

rubber was recorded at periodic intervals at a height of 125 cm from bud union. Soil samples were collected 

before and 6.5 years after planting from each system and analysed for physical and chemical properties. 

Bulk density and porosity of soils were not affected by planting different intercrops while an improvement 

in cation exchange capacity (CEC) and organic carbon status was observed in banana and cover crop 

established areas. An increase in available phosphorus was noticed in all the systems and the availability of 

potassium increased significantly in banana area compared to other systems. The tappability of rubber in 

6.5 years was 43.75% in banana-intercropped areas. Growth of rubber was superior together with banana 

compared to other systems while in tapioca, pineapple and cover crop established areas, tappability was 

37.8, 17.02 and 37.8 % respectively. The study showed that among the three intercrops and cover crop, 

banana intercropping is good for improving growth of rubber followed by cover crop and tapioca. 

Keywords: Cropping systems, Hevea brasiliensis, Intercropping, Physico-chemical properties, Tappability 

Correspondence: Phebe Joseph (Email: phebe@rubberboard.org.in) 

39 

productivity per unit area and the success 

of intercropping in relation to sole cropping 

depends on how existing agronomic 

practices can be manipulated to improve the 

land use efficiency of various intercropping 

systems (Sen et al.,1976; Ofori and Stern, 

1986). The ultimate aim of intercropping is 

not only to obtain additional income but also 

to improve the fertility status in the long run. 

Nair (1999) reported that high output from 

any cropping system will deplete the soil of 

its nutrient store and make the system

46 Natural Rubber Research, 25(1): 46-51, 2012 

METHODS TO IMPROVE ESTABLISHMENT 

SUCCESS AND GROWTH OF GREEN BUDDED 

STUMPS OF HEVEA IN POLYBAGS 

INTRODUCTION 

The green budding technique on rootstock 

of five to six months old is the most 

commonly practised propagation method in 

Hevea. Optimum time for green budding is 

the dry months from January to March in 

the traditional rubber growing regions in 

India. It has been observed that green 

budded stumps when planted in polybags 

often showed high percentage of casualty 

due to dieback of the scion (RRIM, 1964; 

Marattukalam and Varghese, 2000). Some of 

the causes for the dieback of green budded 

stumps were the delay in initiation of lateral 

V.C. Mercykutty and T. Gireesh 

Rubber Research Institute of India, Kottayam - 686 009, Kerala, India 

Received : 2 May 2011 Accepted : 14 June 2011 

Mercykutty, V.C. and Gireesh, T. (2012). Methods to improve establishment success and growth of green 

budded stumps of Hevea in polybags. Natural Rubber Research, 25(1): 46-51. 

Studies were undertaken in the polybag nursery for two successive years to investigate whether indole 

butric acid (IBA) and water enhanced establishment of green budded stumps of Hevea in polybags. Three 

different concentrations viz. 250 ppm, 500ppm and 1000 ppm IBA were used for the study. A simple technique 

of keeping tap root of green budded stumps dipped in fresh water for 4-5 hours before planting in polybags 

was also attempted. Examination of the stumps after four months from application showed that IBA at 500 

ppm and water gave 73.16 % and 66.27% establishment, respectively whereas it was 53.50% in the control. 

IBA at the concentration of 500 ppm and also fresh water treated stumps recorded better height, diameter, 

and number of whorls than the untreated stumps. Dry weight of lateral roots showed better response of 

138% (500 ppm IBA) and 125% (fresh water) over the control. The results of this study indicated higher 

production of lateral roots after the IBA and water treatments and thereby better establishment of green 

budded stumps in polybags. 

Keywords: Green budding, Growth of Hevea, IBA and Water 

Correspondence: V.C. Mercykutty (Email: mercykuttyvc@rubberboard.org.in) 

roots due to progressive desiccation of 

stumps and low carbohydrate reserve 

(Hafsah and Pakianathan, 1979). Delayed 

planting of green budded stumps in 

polybags causes further desiccation and 

reduces viability of the stumps due to water 

loss (Pakianathan and Tharmalingam, 1982). 

To overcome such adverse situations, 

methods were tested to improve the 

establishment success in polybags by 

inducing early rooting and prevent 

desiccation. The objectives of the study were 

to determine the optimum concentration of 

indole butric acid (IBA), a rooting hormone 

widely used in horticultural nurseries to


YIELD PERFORMANCE OF CLONE RRII 105 

UNDER LOW FREQUENCY TAPPING 

IN BO-2 AND BI-1 PANELS 

INTRODUCTION 

K. Karunaichamy, K.U. Thomas and R. Rajagopal 


Hevea brasiliensis Muell. Arg. (Para 

rubber) is the most important source of 

natural rubber (NR). India holds the fourth 

position in NR production and productivity 

in India is the highest in recent years. Land 

productivity of rubber plantation is 

governed by factors like clone, stand per 

hectare and intensity of tapping practices etc. 

The recent increase in NR price has brought 

bright hope to the rubber industry. However, 

increase in the cost of production and 

Received : May 2011 Accepted : November2011 

Karunaichamy, K., Thomas, K.U. and Rajagopal, R. (2012). Yield performance of clone RRII 105 under low 

frequency tapping in BO-2 and BI-1 panels. Natural Rubber Research, 25(1): 52-59. 

In India, cost of production of natural rubber is high due to undulating topography, less favorable agroclimate 

and additional cultural practices. Reduction in cost of production by adopting low frequency tapping (LFT) 

with judicious application of yield stimulants like Ethephon is one of the approaches to make rubber 

cultivation more cost effective. An experiment was laid out in the Experimental Farm Unit of Rubber Research 

Institute of India, Kottayam, Kerala to compare the long term yield response of clone RRII 105 to low 

frequency tapping in BO-2 and BI-1 panels. Cumulative dry rubber yield over eight years under d3 and d4 

tapping frequency with stimulation is comparable to unstimulated alternate daily tapping (d2). There was 

no reduction in yield from the renewed bark compared to virgin BO-2 panel. Total tapping days during the 

study period for d2, d3 and d4 frequencies of tapping were 1149, 780 and 598 days, respectively. Thus by 

adopting d3 and d4 frequencies of tapping, requirement of tappers can be reduced by 32% and 48% 

respectively, compared to alternate daily (d2) tapping. Benefits of adopting LFT are sustainable high yield 

and extended period of tapping on the same panel leading to longer economic life of rubber trees. Adoption 

of LFT is also expected to reduce the impact of the scarcity of skilled tappers in rubber plantation sector. 

Keywords: Ethephon, Hevea brasiliensis, Low frequency tapping, Stimulation, Yield 

Correspondence: K. Karunaichamy (Email: Karunai@rubberboard.org.in) 

shortage of skilled tappers haunting the NR 

industry in India. In some other Asian 

countries tapping alone accounts for more 

than 70% of the cost of production of NR 

(Vijayakumar et al., 2005). India and other 

rubber growing countries are facing 

shortage of skilled tappers and this problem 

is likely to aggravate in future. In such 

situations, grower has to pay very high 

wages to attract the tappers or they leave the 

trees untapped. Increase in cost of 

production and unavailability of skilled


PERFORMANCE OF CERTAIN EXOTIC 

HEVEA CLONES IN KANYAKUMARI REGION 

T.A. Soman, M. Suryakumar, Kavitha K. Mydin* and M.A. Nazeer* 

Rubber Research Institute of India, Hevea Breeding Sub-station, Kanyakumari- 629 851, 

Tamil Nadu, India 

*Rubber Research Institute of India, Kottayam-686 009, Kerala, India 

INTRODUCTION 

Introduction and evaluation of Hevea 

clones of proven yield potential 

domesticated in other rubber producing 

countries have been one of the methods 

adopted for crop improvement in the 

Rubber Research Institute of India. So far, 

127 such clones evolved in Malaysia, 

Indonesia, Sri Lanka, China, Ivory Coast, 

Brazil, Thailand and Liberia have been 

introduced and are under various stages of 

evaluation under the local agro-climatic 

conditions (Varghese et al., 2006). Most of 

these introductions were made by bilateral 


Soman, T.A., Suryakumar, M. Mydin, K. K. and Nazeer, M.A. (2012). Performance of certain exotic Hevea 

clones in Kanyakumari region. Natural Rubber Research, 25(1):60-67. 

Growth and yield performance of nine recently introduced clones of Hevea and two established clones were 

evaluated in a large-scale trial in the Kanyakumari District of Tamil Nadu. Significant clonal variations for 

growth, yield and bark anatomical traits were evident. Four clones, two each introduced from Malaysia 

(PB 255 and PB 314) and Ivory Coast (IRCA 109 and IRCA 111), exhibited provising growth and yield in the 

panel B0-1. However, on completion of eight years of tapping, the yield performance of PB 314, IRCA 109 

and IRCA 111 were found to be on par with the control clone RRII 105. The significant yield improvement 

show by PB 255, could be considered as a real reflection of the high yield potential of PB 255. Based on the 

vigorous growth, early tappability, excellent bark characteristics, stability parameters, consistent high yield, 

high summer yield etc. PB 255 was rated as the best selection for the Kanyakumari region. High girthing 

clones, in general, showed lower number of latex vessel rows, but higher values for both these characters 

were found combined in PB 255. 

Keywords: Early tappability, Girth increment, Meteorological variables, Rubber yield 

Correspondence: T.A. Soman (Email: soman@rubberboard.org.in) 

and multilateral clone exchange programs 

under the auspices of the International 

Rubber Research and Development Board 

(IRRDB) and Association of Natural Rubber 

Producing Countries (ANRPC). 

Kanyakumari region of Tamil Nadu is 

characterized by an agro-climate distinct 

from other regions in the traditional rubbergrowing 

belt in the country. Rain is moderate 

(less than 2000 mm), but the well-distributed 

rainfall pattern associated with fairly good 

summer showers provide a congenial agroclimate 

for the good performance of rubber. 

Almost half of the annual precipitation is


POLYHOUSE TECHNOLOGY FOR PRODUCTION 

OF HEALTHY PLANTING MATERIALS OF RUBBER 

V.C. Mercykutty, Kavitha K. Mydin, Shammi Raj, C. Bindu Roy and P.M. Priyadarshan* 


*Central Experiment Station, Rubber Board, Chethackal, Ranni-689 676, Kerala, India 

INTRODUCTION 

Bud-grafted plants in the rubber nursery 

need extreme care during the early stages of 

their development. During adverse climatic 

conditions like heavy rainfall and high/low 

temperature, nursery plants are affected by 

diseases and pests resulting in low and 

delayed bud break followed by uneven 

growth of scion that leads to shortage of 

planting materials in rubber nurseries. 

It is worthwhile to examine the growth 

and development of bud-grafted plants 

Received : 21 March 2011 Accepted : 13 July 2011 

Mercykutty, V.C., Mydin, K.K., Raj, S., Roy, C.B. and Priyadarshan, P.M. (2012). Polyhouse technology for 

production of healthy planting materials of rubber. Natural Rubber Research, 25(1): 68-76. 

Two polybag nursery experiments were conducted at the Central Experiment Station of the Rubber Research 

Institute of India, Chethackal to compare sprouting and growth of green and brown-budded stumps of 

rubber (Hevea brasiliensis) planted in polybags kept in polyhouse and outdoors. Budded stumps generated 

from both green and brown budding techniques recorded early emergence of buds and better and uniform 

growth of scion in polyhouse conditions. Plants raised in polyhouse were better in terms of height of scion, 

diameter of stem, number of whorls, number of lateral roots and total biomass content. The study showed 

that the quality of plants improved when grown inside a polyhouse. 

Growing plants in polyhouse enabled to overcome intra-clonal variability in growth of bud-grafted plants 

to certain extent. It protected the grafts from diseases, reduced mortality due to adverse weather conditions 

and ensured production of healthy plants. The environmental conditions in the polyhouse had no adverse 

effect on further growth and development in the field and thereby ensuring rapid production of healthy 

planting materials in large-scale cultivation. In addition to saving manpower, this modern technology is an 

eco- friendly approach by limiting the use of fungicides inside the polyhouse condition. 

Keywords: Budgrafted plants, Hevea, Polyhouse, Polyvinyl sheets 

Correspondence: V.C. Mercykutty (Email: mercykuttyvc@rubberboard.org.in) 

under controlled conditions, especially in 

polyhouse, that can be reused year after year. 

A polyhouse is a framed structure of UVstabilized 

rigid transparent polythene sheets 

(200 micron thickness) covered from all sides 

in which plants can be grown under 

sufficiently controlled environmental 

conditions. The sheet is inserted 8-10 cm 

under soil for proper sealing of the 

polyhouse. The structure is supported with 

vertical iron rods and the use of HDPE pipes 

helps to form a semi-circular design. The 

covering of nursery areas with polyvinyl


DETECTION AND ISOLATION OF GOOD QUALITY 

DNA FROM THE LATEX OF HEVEA BRASILIENSIS 

INTRODUCTION 

A. Thulaseedharan, R.S. Sajeevan and A. Saleena 

Rubber Research Institute of India, Kottayam-686009, Kerala, India 

Natural rubber (NR) is produced in the 

latex vessels present in the bark of the rubber 

tree, Hevea brasiliensis (Kekwick, 1989). NR 

latex is a milky cytoplasm which is exuded 

from specialized cells called latex vessels or 

laticifers. The detailed ultra structure of 

Hevea latex vessels indicates that the 

expelled latex is part of a specialized 

hydrated and progressively degenerating 

cytoplasm (Auzac and Jacob, 1989). The latex 

vessels of H. brasiliensis are specialized cells 


Thulaseedharan, A., Sajeevan, R.S. and Saleena, A. (2012). Detection and isolation of good quality DNA 

from the latex of Hevea brasiliensis. Natural Rubber Research, 25(1): 77-85. 

The laticiferous system of natural rubber (NR) Hevea brasiliensis has abundant transcripts of several genes, 

mainly those involved in rubber biosynthesis and plant defense. So far no detailed study to understand the 

mechanism behind this transcript abundance has been made. There is little evidence for the presence of 

DNA or active nuclei in large numbers in the latex expelled during tapping. There is also no protocol 

available for the isolation of genomic DNA from NR latex which contains large amounts of DNase. The 

present study explore the presence of genomic DNA in Hevea latex expelled on tapping and isolation of the 

same following a modified CTAB based DNA isolation protocol. Initially, the whole latex was treated with 

CTAB buffer and DNA isolation was carried out. Further different fractions of latex after seperated by 

centrifugation. High molecular weight DNA was obtained from the bottom fraction. No DNA was obtained 

from the whole latex or from the serum fraction of any of the treatments. The quality and concentration of 

the isolated DNA was better when latex was pre-treated with a latex specific DNA isolation buffer and the 

DNA was isolated from the bottom fraction. The DNA isolated was fully digested with DNase1 treatment. 

When this DNA was used as template for PCR using hevein gene specific primers, the amplified products 

were similar to those amplified from leaf DNA. This is the first report on detection of genomic DNA from 

NR latex and developing a successful protocol for the isolation of good quality genomic DNA from the 

latex of Hevea brasiliensis. 

Keywords: DNA isolation, Hevea brasiliensis, Natural Rubber latex, PCR amplification 

Correspondence: A. Thulaseedharan (Email: thulaseedharan@rubberboard.org.in) 

77 

derived from the fusiform initials of the 

cambium (De-Fay et al., 1989) and they 

contain the machinery to convert simple 

sugars into rubber particles (cis-1,4polyisoprene) 

(Chow et al., 2007), which is 

about 35% of the latex. 

Being cytoplasm, NR latex contains 

several gene transcripts with abundance of 

those involved in rubber biosynthesis and 

plant defense genes (Kush et al., 1990; Chow 

et al., 2007; Ko et al., 2003). While several 

cellular organelles are seen in the latex, there


HISTOCHEMICAL CHANGES IN EMBRYOGENIC 

AND NON-EMBRYOGENIC CALLI 

OF HEVEA BRASILIENSIS 

INTRODUCTION 

P. Kumari Jayasree, C.P. Reghu, R.G. Kala and A. Thulaseedharan 


Rubber tree (Hevea brasiliensis) is the 

widely cultivated species as a commercial 

source of natural rubber. Over the past years, 

tremendous advancement has been made in 

latex yield through conventional breeding 

and by introducing several modern clones 

with high yield potential. However, many 

desirable secondary traits are limited due to 

the narrow genetic base. Genetic 

transformation provides a viable alternative 

approach for genetic improvement in this 

perennial tree species. However, an essential 

pre-requisite to the success of this approach 

is the availability of a suitable target tissue 

Received : 22 February 2012 Accepted : 14 May 2012 

Jayasree, P.K., Reghu, C.P., Kala, R.G. and Thulaseedharan. A. (2012) Histochemical changes in 

embryogenic and non-embryogenic calli of Hevea brasiliensis. Natural Rubber Research, 25 (1): 86-90. 

It is well established that the accumulation of storage products is a reliable marker for the classification of 

embryogenic cells. The present study characterizes embryogenic and non-embryogenic calli of Hevea 

brasiliensis through histochemical localization of storage reserves. Inoculation of immature anthers on callus 

induction medium induced type I (soft and watery) and type II (semifriable / compact) callus. Observations 

showed that embryogenic callus consists of small cells with prominent nuclei, while non embryogenic calli 

were characterized by large cells having prominent nuclei. Histochemical examination revealed the 

accumulation of significant amount of storage starch, lipids and proteins which were dispersed throughout 

the cells of embryogenic calli, particularly, at later stage than in early phase, whereas low level accumulation 

of major storage reserves was detected in non-embryogenic calli. 

Keywords: Embryogenic callus, Hevea brasiliensis, Histochemical characterization, Non- embryogenic callus, 

Storage reserves 

Correspondence: P. Kumari Jayasree (Email: kumarijaya@rubberboard.org.in) 

for genetic transformation whereby plants 

can be regenerated from single transformed 

cells through somatic embryogenesis. 

Embryogenic callus is generally considered to 

be a highly desirable target tissue for genetic 

transformation because of high population of 

totipotent cells for single cell origin of somatic 

embryos (Merkle et al., 1995). 

Induction of embryogenic callus is the 

first and crucial step during somatic 

embryogenesis, which largely determines 

the success of embryogenesis. In most of the 

hard wood species, embryogenic callus 

formation is very difficult and Hevea is not 

an exception (Blanc et al., 1999). Screening


TRENDS IN WAGE SHARE IN THE CONTEXT 

OF LABOUR SHORTAGE: 

THE CASE OF TAPPING WAGE SHARE IN RUBBER 

SMALLHOLDINGS SECTOR IN KERALA 

INTRODUCTION 

Binni Chandy and Tharian George K 


Growing market uncertainties have 

become an important characteristic of all 

Received : 31 August 2011 Accepted : 30 May 2012 

Chandy, B. and George, K.T. (2012). Trends in wage share in the context of labour shortage: The case of 

tapping wage share in rubber smallholdings sector in Kerala. Natural Rubber Research, 25(1): 91-99. 

The study is an attempt to understand the trends in the share of tapping wages in farm income of the rubber 

smallholding sector in the backdrop of uncertainties in NR prices and the reported shortage of tapping 

labour. The database consisted of documented field level time series data on wages of smallholdings from 

primary sources and published official data on productivity and price during the 30 year period which is 

divide into pre-reforms (1980-1981 to 1990-199) and post-reforms (1991-1992 to 2009-2010) phases. The 

tapping wage share is defined as the share of annual tapping wages in annual farm income of the 

smallholdings. The study found that the average tapping wage share was 19.63 per cent. The tapping wage 

share was comparatively higher during the pre-reforms phase (24.18%) compared to the post-reforms phase 

(18.11%). The trends in comparative growth rates and instability indices of real values of the selected variables 

over the two phases showed that during the pre-reforms phase except the price (– 2.04 %) and wage share 

(– 0.51 %), other variables showed positive growth rates. But during the post-reforms phase while price 

recorded a positive growth rate (2.25 %), wage share grew at a negative growth rate (– 0.24 %) with a 

comparatively higher growth rate in wages (4.73 %). During the 30 year period also the growth rate of wage 

share showed a negative growth rate (–1.25 %) despite the positive growth rate in real wage (2.29 %). The 

instability indices showed that during the pre-reforms phase wage share (9.02) was the most unstable 

variable. During post-reforms phase though wages were comparatively stable (7.51) wage share was 

highly unstable (30.87). The correlation analysis showed a negative and significant coefficient of correlation 

(– 0.74) between farm income and wage share during the 30 year period. The study revealed that the 

tapping wage share in Kerala’s rubber smallholding sector not only lagged behind the significant strides 

made in the real values of farm income and wages but also grew at a negative growth rate during the 30 

year period. 

Keywords: Farm income, Real values, Rubber smallholdings, Tapping labour, Wage share 

Correspondence: Binni Chandy (Email: binni@rubberboard.org.in) 

91 

primary commodities since the second half 

of the 1990s. The implications of this 

phenomenon have attracted considerable


EFFECT OF STORAGE ON PROPERTIES OF 

NATURAL RUBBER SHEETS IN TRIPURA 

Joy Joseph, *Leelamma Varghese, S. K. Dey and *K. T. Thomas 

Regional Research Station, Rubber Research Institute of India, Kunjaban - 799006, Agartala, India 

*Rubber Research Institute of India, Kottayam – 686 009, Kerala, India 

INTRODUCTION 

Rubber tree (Hevea brasiliensis) is the 

most important source of natural rubber, 

which has commercial importance in the 

production of more than 45,000 items. H. 

brasiliensis, a native of the Amazon river 

basin, is traditionally cultivated in Kerala 

and Kanyakumari district of Tamil Nadu in 

India. The agroclimatic conditions of northeast 

region are unique and are suitable for 

rubber cultivation. Among north-eastern 

states, Tripura has 50070 ha plantation with 

an average production of 23280 t (Rubber 

Grower’s Companion 2011) and is first in 

respect of area as well as production of 

natural rubber. 

Received : 15 May 2011 Accepted : 20 July 2011 

Joseph, J., Varghese, L., Dey, S.K. and Thomas, K.T.(2012). Effect of storage on properties of natural rubber 

sheets in Tripura. Natural Rubber Research, 25(1): 100-106. 

Packed ribbed smoked sheets (RSS) as (50 kg bales) were stored at different locations of Tripura under 

normal conditions for a period of 18 months and changes in the quality parameters were compared with 

bales stored under controlled conditions. Sheets kept under normal conditions were affected with mould 

after five months of storage. No mould growth was observed in bales stored under controlled conditions 

even after one year of storage. However, slight mould growth was observed on the surface of the bales after 

one year. Mooney viscosity, initial plasticity, strength and gel content of the sheets increased with storage 

whereas the plasticity retention index decreased on storage. Acetone extractables were decreased slightly 

due to storage. 

Keywords: Controlled conditions, Natural rubber, North-East India, Storage, Sheet bales 

Correspondence: Joy Joseph (Email: joyjoseph@rubberboard.org.in) 

In India, natural rubber is available as 

ribbed smoked sheets, technically specified 

rubber, crepe rubber, centrifuged latex, 

creamed latex and preserved field latex. 

Among these, the major marketable form is 

ribbed smoked sheets (about 71%) as it can 

be produced by the simplest method of 

processing. Rubber sheets are sometimes 

stored for long periods by growers, dealers 

and also by government agencies 

anticipating better price while manufactures 

store rubber for ensuring sufficient stock for 

production (Mohankumar, 1999). 

The storage of raw natural rubber affects 

its properties, the most important being an 

increase in Mooney viscosity, commonly 

referred to as storage hardening (Wood,


DISTRIBUTION OF PROTEIN-STORING CELLS IN 

THE BARK TISSUE OF HEVEA BRASILIENSIS IN 

RESPONSE TO TAPPING PANEL DRYNESS AND 

STIMULATION 

Vinoth Thomas, C.P. Reghu, V. Divya, P.K. Ambily and R. Krishnakumar 


INTRODUCTION 

Hevea brasiliensis, the prime source of 

natural rubber, is harvested through 

controlled wounding (tapping) of latex 

vessels present in the bark tissue (Fig. 1). The 

continuous injury of the bark leads to a series 

of anatomical and histochemical changes in 

the cells adjacent to the wound leading to 

Received : 16 May 2011 Accepted : 21 November 2011 

Thomas, V., Reghu, C.P., Divya, V., Ambily, P.K. and Krishnakumar, R. (2012). Distribution of protein 

storing cells in the bark tissue of Hevea brasiliensis in response to tapping panel dryness and stimulation. 

Natural Rubber Research, 25 (1): 107-114. 

Latex from Hevea brasiliensis is harvested through controlled wounding (tapping) of the latex vessels present 

in the bark tissue. The continuous injury on the bark leads to regeneration of the tissue involving various 

anatomical and biochemical changes in the cells adjacent to the wounded bark. In general, trees of high 

yielding Hevea clones when subjected to over-harvesting latex are susceptible to tapping panel dryness 

(TPD), resulting into the cessation of latex flow. The actual mechanism involved in the partial or complete 

cessation of latex flow in the TPD affected trees is still obscure. 

The distribution and occurrence of protein-storing cells (PSC) in the secondary phloem (bark) are a common 

phenomenon which is considered as an end product of various translocation mechanisms taking place in 

the bark tissue. In healthy trees of rubber, the PSC was distributed in one or two layers surrounding the 

phloic rays and also adjacent to sieve tubes, where as its density was increased in TPD affected trees (4-5 

layers) as well as in TPD affected regions of stimulated trees. The PSC were in close association with the 

sieve elements which were an important in the movement of photosynthates. Occurrence, structure and 

distribution of PSC and its functional role in Hevea bark tissue with respect to TPD and stimulation were 

studied and discussed. 

Key words: Hevea brasiliensis, Protein storing cells, Stimulation, Tapping panel dryness. 

Correspondence: Vinoth Thomas (Email: vt@rubberboard.org.in) 

107 

bark regeneration as the cambium is 

undisturbed (Thomas et al., 1995). In general, 

trees of high yielding clones of Hevea when 

subjected to over-harvesting latex are 

susceptible to a disorder termed tapping 

panel dryness (TPD) (Fig. 2), resulting in the 

cessation of latex flow from the tapping cut. 

Towards the end of the economic life span


EVALUATION OF POLYCROSS SEEDLINGS OF 

PREPOTENT HEVEA CLONES POTENTIAL FOR YIELD 

IMPROVEMENT AND DROUGHT TOLERANCE 

INTRODUCTION 

M. A. Mercy and Kavitha K. Mydin 


Breeding in Hevea aims at evolving 

clones for specific objectives and 

environments. The efforts for rapid genetic 

improvement are often hindered due to the 

perennial nature of the crop where 

procedures are often lengthy and laborious 

(Tan, 1987; Simmonds, 1989; Varghese and 

Mydin, 2000) and hence early evaluation 

techniques must be practised in seedling and 

clonal nursery screening for shortening the 

breeding cycle in Hevea. Seedling 

morphology is very important in the 

Received : 20 March 2011 Accepted : 25 May 2011 

Mercy, M.A. and Mydin, K.K. (2012). Evaluation of polycross seedlings of prepotent Hevea clones for yield 

improvement and drought tolerance. Natural Rubber Research, 25(1): 115-121. 

A seedling nursery evaluation of nine sets of half-sib seedlings was conducted at Rubber Research Institute 

of India. The family-wise performance of the progenies was assessed by considering their juvenile yield on 

test tapping during peak and summer seasons along with seedling girth. An attempt was also made to 

study their drought tolerance potential by conducting a pot culture study in the second phase along with 

one set of seedlings of assorted origin. Growth parameters like plant height, girth and number of leaves 

were recorded at regular intervals during summer and non-summer periods. Visual scoring leaf yellowing 

was done in pot culture. From nursery evaluation, 126 potential seedlings out of 397 (31.7 %) could be 

identified with high summer yield. In pot culture study, the highest number of seedlings with green leaves 

was in the family of PB 28/83. The performance of the family of assorted seeds was inferior to polycross 

progenies throughout the period. The progenies of clones PB 28/83 and PB 215 were identified as ideal 

populations for selection and further detailed studies. 

Key words: Drought tolerance, Girth, Hevea brasiliensis, Juvenile yield, Polycross seeds 

Correspondence: M.A. Mercy (Email: mercyma2006@gmail.com) 

115 

improvement of perennial crops and 

seedling vigour gives an indication of the 

vigour of clones after budding. Good 

immature vigour is one of the most 

important attributes associated with yield 

potential in rubber and is one of the early 

selection criteria in Hevea breeding 

programmes. Being an outcrossing perennial 

tree, Hevea brasiliensis offers abundant scope 

for producing natural polycross seeds, which 

are recommended for planting in marginal 

lands as the heterogeneity of the seeds 

becomes advantageous in imparting stability 

of performance under adverse conditions.

(hevea brasiliensis) clones - Rubber Board

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