‘Bivoltine is not for small farmer’- TH. Somasekhar

Interview by GK. Rajesh

Dr. TH. Somasekhar is India’s leading silk expert. Recipient of the Louis Pasteur Award (2005) of

Dr. TH. Somasekhar

International Sericulture Commission, he led the country’s silk technology research & development for fifteen years as Director of Central Silk Technological Research Institute (CSTRI). Dr. Somasekhar is a PhD in Fibre Science from University of Strathclyde, Glasgow. He obtained B Tech and M. Tech from Bangalore University and Indian Institute of Technology, New Delhi respectively. In an illustrious career spanning more than three decades he has held many positions such as Head of Textile Technology Division, Silk & Art Silk Mills Research Association, Mumbai, Senior Scientific Officer of Ahmedabad Textile Industry’s Research Association, Chief Technical Advisor of M/s. Swan Silk, Ltd., Bangalore etc. Dr. Somashekar is an internationally renowned expert on textiles especially silk. He is widely travelled and associated with all silk producing countries. In this interview, recorded at his residence at Bangalore, India, Dr. Somasekhar spoke at length about India’s sericulture and silk industry, demystifying popular perceptions on the future of silk as an apparel fibre.

Dr. Somasekhar can be contacted at: thsomashekar@gmail.com       

GK: Sericulture is an important agro-industry in many parts of India, especially the South. A large number of stake holders such as farmers, silk reelers, weavers, traders and other manual labourers are involved. Silk has been considered a very important commodity by its Royal patrons and during British Rule. The fact that the first commodity board in independent India was constituted for silk is indicative of the importance attached to it. But the industry has been showing a declining trend over past few years. What do you think are the reasons?

Dr. Somasekhar: For last few years particularly for a decade sericulture has been declining and the decline is due to various reasons. For example in Karnataka, a large track of land which was under sericulture in the past has been lost. The main reason around Bangalore Rural district has been urbanisation. Now the new Bangalore international air port has come up. As a result of that development the lands around it have gone for various purposes other than sericulture. Another reason is perhaps sericulture all along has been a labour intensive activity and we have learnt from experience of other countries that sericulture has thrived and survived as long as the contribution of family labour was in bulk. As it went towards engaging labour from outside the economics has not been working out and then also we have known that as the standards of living among the farming community has gone beyond a certain level sericulture has been lost. Another aspect is that there are many other alternatives for the farming community where, with less effort they are able to earn more. See for example in Karnataka there are more profitable alternatives like horticulture, floriculture etc with ready market and less risk. And then we have not been able to provide a stable market for the producer. The cocoon and raw silk prices fluctuate; something that they never wanted. They have always asked, ‘give us a stable price’.

Another thing that has happened in recent years is imports. Large scale imports have affected the local industry and that has been a major factor. As a nation we may have various compulsions for allowing imports- particularly after globalisation of the markets we have to participate survive and fight it out in the open market and that is something which has not been conducive for the progress of sericulture. So as a result we have seen all these factors put together in various dosages contributed to the decline of sericulture.

Globalisation, in fact could have been an opportunity rather than a threat for development. Many domestic industries utilised it either as a means to get cheap imports of essential raw material or as an avenue for large scale export of domestic goods. But silk industry seems to have failed miserably in utilising this opportunity. What is your observation?

We have seen that while imports have increased the exports have not been increasing. Exports in quantity terms have come down. The case of raw material exports is different. For example silk waste export doesn’t help the local spun silk industry. As such the number of spun silk mills in the country has come down. We had a string of spun silk mills numbering almost a dozen in the private sector. They have all closed down now. The reason is they are not getting raw material at a price which is economical to them. We have all the technologies imported. We have Japanese technology, Italian technology for de gumming and spinning and considerable amount of money have been invested in getting the suitable machinery, the line of machines, required for spun silk manufacture.

Then we also see in the recent years that the import duties on raw silk have been brought down to almost 5% and this is going to have a major impact, a perceivable effect on the growth of the industry. The reason is it is not that we will be getting imported silk at a cheaper rate like in the past. Gone are the days when we could import low quality silk when a lot of silk was made available to weavers at import prices as low as $12-16 per kg. Today the prices have gone up beyond $37-38. So what is happening? We are having bulk imports at high prices. So this is something which is going to create problems. Our own production is not much and at least the farmer and silk reeler would have commanded a better price if the imports were not there. The import price is also closely linked to the availability of local silk. When the local silk availability is low, prices automatically go up and import prices also will be at a higher side. These are the changes that have taken place and sericulture is taking a beating from all angles.

India obtained a couple of anti-dumping sanctions against China in case of cheap imports of silk yarn. Do you think China has been dumping silk in India?

You can’t say dumping. A few years ago cheap silk was coming. But today silk is not cheap. The silk we are importing is expensive. Why that is happening is because we have a lot of demand. There is a huge gap between demand and supply. Our own raw silk production is not meeting the requirement. 7 to 8000 tonnes of raw silk is being legally imported. Our production may not be more than ten thousand tonnes, though we claim that we have 17 to 18,000 tonnes of raw silk. On observing the availability in the field that is the farmer activity, cocoon market activity reeler and weaver activity, I get a feeling that we don’t have the kind of raw silk production that we clam to have. That is the reason we are forced to import so much of raw silk. Our requirement has always been estimated around 24 to 25,000 tonnes. If we had 17 to 18,000 tonnes local production 7 to 8,000 tonnes should have been imported. My own understanding of the weaver’s situation is that they are all not doing silk alone. This is because of the increased prices and as ordinary people can’t afford pure silk. So there is a lot of imitation material and combinations. Cotton and silk, Polyester and silk, polyester alone . . . but you have the same designs. Thus the prices have decreased the demand for pure silks. Therefore I feel that this 7,000 to 8,000 tonnes added to our own requirement may not be 25,000 tonnes. It could be far less. Our own production should be around 10 to 12,000 tonnes and our total requirement should be around 18 to 20,000 tonnes.

As I understood, in the past, there were lot of loop holes in imports and large quantities of raw silk were getting into the country through unofficial channels. But all those have been plugged now and the situation also has changed. There is no incentive for people to import silk when the price is high. Even in China, they are not giving you silk less than $ 37 to 38. The overall market situation is such that we have a gap and because of our own production being low, this gap is being filled by imports.

I was in China a few years ago and I had an opportunity to discuss with the companies which manufacture and sell silk. They have lot of buyers in India. I asked them why have they increased the prices, and we can’t afford silk at $ 37 to 38 and even more. The answer I got was: “after all our interest is to sell more. But we will have to see at what prices we are producing raw silk”. The MD of the company told me that for past few years they have been forced to give double the salaries being paid until then. That has (almost) doubled the cost of production. The standards of living in China have increased and the situation that existed in the past is no more relevant. Given this kind of a situation silk is becoming an expensive material and I don’t think it will be cheap in the future and the kind of prices that we have seen in the past may not come again. In such situation countries like India may see further drop in production. We may feel that China has a monopoly. But in the years to come it is quite possible that their interest may also go down and the total silk availability come down.

Is silk going to stay for ever?

I foresee a situation where we will definitely have less and less silk in the coming years and we have to live with it and kind of decide where we need silk. This is going to be a big question. Do we need silk for apparels? In the recent years we see a whole lot of uses of silk other than apparels. With the total availability coming down we should also look at other possibilities which could open opportunities for expensive silk in much better and more important uses. In bio-medical engineering silk is seen as a scaffolding material. It helps growth of cells in the body. Can we look at these possibilities and expand into these areas? We need not worry oh! We are losing silk. In the years to come we should also plan out sericulture from these angles. When we look at silk for apparel purposes the quantity requirements are too huge and we try to increase productivity, leading to use of large quantities of inorganic fertilizers. That is how the quality of land deteriorates. Diverting silk to non apparel purposes will reduce the quantity demand pressure. This would be far more scientific. When we use silk for bio-medical purposes there shouldn’t be even traces of inorganic material in it. This reduces pressure on environment. Perhaps more such uses may arise.

India implemented at least two ambitious externally aided projects: the Karnataka Sericulture Project (KSP) and National Sericulture Project (NSP) both were declared failure by those who did final assessment. Where did we go wrong? What are the lessons?

KSP & NSP were in many ways projects for the sericulturist, for upgrading himself, to adopt new practices and to accept new technologies. The model of sericulture that we had is something very important. In fact I had projected three models of sericulture existing in different parts of the world.

1. The Indian model which consist of small producer and small converter

2. The Chinese model which has small producer and large converters

3. The Japanese model (that has been practiced by Brazil) where you have large producers and large converters

The inputs that we gave in KSP & NSP were mainly to the Indian model. That is small producer – small converter. The support that was given to the industry was not much. The planners at that time thought that we have to support the supply side and that is how all the support was given to the farmer. That was to strengthen the base. What has happened is there for you to see. Now, while looking back one gets the feeling; should we have supported the demand side, for that would have created a demand pull and perhaps resulted in better sericulture?  All said and done, there is an absolute need that we change the Indian model of small producer & small converter. May not be totally towards the Chinese or Japanese side; but somewhere in between. For this I had proposed certain changes. There was a committee which had looked into these things and given a request to the Research Coordination Committee (RCC) of central Silk Board which was chaired by Prof. Chopra. He said that the suggestions of the committee should be put into practice at least by the leading states (Karnataka, Andhra Pradesh and Tamil Nadu). But I don’t think that has happened. We haven’t made course corrections. We tend to stay where we are. That is not good. We should adopt ourselves to the changes that are taking place. Everything is market driven today. We can’t say ‘I have a poor farmer, please buy’. I can’t go and ask people ‘buy Indian silk’. If the demand is met, if the quality is met, any silk is acceptable to a customer. Market doesn’t wait for you.

The focus of both NSP and KSP was popularisation of Bivoltine (BV) sericulture. India received a lot of technical support from abroad, especially from Japan and until recently Japanese stayed in India to ‘bivoltinise’ Indian sericulture. In this quest we have grossly over looked the strengths of local varieties of silk worm: the multivoltines and cross breeds etc. Given that the current percentage of diffusion of Bivoltine hybrid in the country is as low as around 10%, what is your assessment on India’s strategy on BV popularisation? How important is BV sericulture to India?
I don’t say, looking at the Indian sericulture, the situation is very conducive for bivoltine. Even in Karnataka we can practice only two crops of bivoltine out of 5 crops per year. Thus bivoltine is not favoured so much, climate wise.

We put in efforts since 1975 for developing Bivoltine sericulture in India. Beginner’s luck, you can say, we had very good results with bivoltine. But we have not been able to sustain it. As a person with long term association with silk industry, I would say that bivoltine is not for small scale farmer. That means bivoltine is not for our model of sericulture. Our farmers are poor. They don’t have the strength to absorb the technological advancements. They don’t have the capacity to invest. Under the project we supported them technically, financially and by way of extension. All these helped them to get the result which was very good. But the moment all these supports were withdrawn after the project it went back to square one.

We were quite successful in developing bivoltine for tropical conditions. The races we developed in Mysore were very good. There is no doubt about it. But the performance of Cross Breed (CB) was exceptionally good. Even today it is close to bivoltine and without much effort. Now the farmer realise why should he take all the trouble for bivoltine when there is no market for it. When he goes to the market, he s a loner, for very small quantities of bivoltine comes there. As a result there is not a demand for his product. Instead of that CB has give good results. Now the question is ‘was bivoltine developed for the improvement of CB?’ Honestly I feel: YES. Looking from both farmer’s and reeler’s side, yes it was. From our old multi-bivoltines like PM X NB4D2 etc., PM X CSR2 is a big jump. As that has happened I am quite happy even if bivoltine is not there. At least there has been a significant improvement in CB production which has helped the economics of the farmer. If cross breed is the answer, we can use BV for improvement of CB. So I still feel it is a big improvement and we should recognise that fact and then we should focus more on the growth of the industry in these lines rather than beating only BV

But the now celebrated Cross Breed (Kolar gold) has not been a research breakthrough. This has been a contribution from the graineurs.

Yes. This is the point. In research we had aimed at something and the fall out has been something else. We have succeeded in research. It is only the extension and transfer and sustenance of this knowledge at the farmer level (we have failed). I am not talking about a small number of farmers who are always under scrutiny and support. I am talking about farmers at large. But the entry of PM X CSR 2 and PM X CSR 4 has changed the whole situation.

Sericulture research has been a prerogative of Central Silk Board, as the government money for research goes to CSB. Has CSB been monopolising sericulture research in the country?

The fact is that apart from CSB research institutes other institutes were not developed to carry out bivoltine research. They didn’t have that kind of background. Where ever you talked about Bivoltine sericulture a scientist found elsewhere was from CSB or formerly from CSB. Two state institutes came up; one in Karnataka and the other in AP. Basically they were all meant for carrying out applied research. Sericulture research is basically applied. During the NSP period CSB invited proposals from umpteen numbers of universities. Some 80- 100 projects were approved and funds were made available. But their interest dried up after the project. They didn’t pursue it and try to get funding from elsewhere. Even today CSB supports research from universities but not to the extent one has been during NSP period. The bottom line there is the interest shown by people.

CSB dint monopolise any research. There was no need. Whatever facilities (equipments and man power) created in institutes and universities during NSP were all limited to the project period. Afterwards they haven’t really done much. The universities also don’t have any long term research plans. Research in our country has been influenced by the demands that have come up. There was this need to expend. That is we needed to produce more, reduce imports. This is the kind of situation that influenced our research. So we addressed productivity and quality. I agree that productivity and quality are not achieved at the final stage. One has to work from the beginning. But that kind of effort has been less. Again the interest of individuals also matter. Large number of scientists would like to delve more on applied areas rather than basic areas because they all feel that the results are quicker and they would be able to show something to the people. The number of people who have shown interest in basic research is less. It is not that we don’t have facilities for basic research in CSB. We do. Basic research is time consuming. You don’t get results over night. So we need people interested in these areas. The pressure of the market shouldn’t be coming to these people. Let the applied people take care of the market situation. I think the CSB would do well to create in each of its research institutes in Berhampore (West Bengal), Mysore (Karnataka) and Pampore (J&K); certain number of people and groups to go into basic research.

It was also thought during the NSP period (as I remember) to entrust universities with basic research. Universities were not expected to do applied research. But that thought didn’t materialise. There were wrong decisions made too. The Karnataka Sericulture Development Institute (KSSDI) later on became KSSRDI (Karnataka Sericulture Research and Development Institute). The research part was not there as it was conceived during the KSP period. The KSSDI was supposed to take out the output of Central Institute and ‘package’ for field requirements. But that responsibility was not taken by KSSDI. It became KSSRDI and became a competitor to Central Institute. That wasn’t required. Today there are problems. They are not able to get funds for salaries. A re-look is desirable and possible even today. KSSRDI could drop the ‘R’ and become a sequel to the research that is done at Mysore institute. Same holds good for APSSRDI of Andhra Pradesh. Their job is very important.

Indian silk reeling industry is visibly in peril. The farm sector of sericulture seems to have stolen the entire attention of policy makers, leaving silk reelers in hardship. Apparently the obsolete technologies prevailing in the reeling sector has made it incapable of absorbing whatever quantities of high quality bivoltine cocoons produced in the country. What has been happening to the reeling sector?   

For the reeling industry to do well, quality of cocoons is primary. In raw silk production, 90-92% of cost of production is cocoon price (during normal times). Sometimes it can be even more than 100% where the reeler looses. He can only be compensated by selling by-products. Unless you have good quality cocoons it becomes impossible for the reeler to adopt new technologies.  Central Silk Technological Research Institute (CSTRI) Bangalore developed multi-end reeling package and as many as 300 or more small units (which was the economic size at that point of time) were manufactured.   They were all planted in a number of reeling areas. The quality of yarn came out of them was good. Only thing was the way the BV has not been able to influence the (cocoon) market, multi-end raw silk could not influence the raw silk market. The ‘influence factor’ comes with quantities in the market. Quantity influences the market. If BV has to influence, it has to be made available in very large quantities. Similarly multi-end silk has to be made available in very large quantities.

For the reeler, when he goes to the market, his buying ability restricted by the amount of money he has. None of these small units enjoy the kind of working capital support the bigger industries enjoy. We have worked on this also. There was a scheme to support these people. We went to banks, talked to them and some kind of support was made available. But still the reeler lacks the much needed large working capital base. Today it is once in 2-3 days the reeler has to go to the cocoon market. Buy cocoons, convert to silk, and sell silk and again go back to buy cocoon in 2-3 days. Whereas in the organised sector; it is at least a couple of months. A small reeler who is producing 10 kg silk per day would require at least 70 kg cocoons and if he has to survive well he needs to have a stock for 20-25 days. That means 1.5to 2 tonnes of good quality cocoons, which would cost at least Rupees 35 to 45 lakhs. Is this kind of money available to our reeler? That is why he is finding it difficult. Our own cocoons, for the quality they have, are the highest priced of the whole world. Nowhere in the world cocoons are as expensive as in India.  That’s the reason why the reeler has not been able to change and he continues to work in a dirty situation with smoke, smell and all this.

This is where we have to look at the models of sericulture. There is a large number of people working in this sector. We can’t go on like this, talking about taking care of these many people. See, in the years to come frankly speaking, if you want to take care of these people as a state, you have to give them alternate areas to work. Take them out of this misery and keep only the required number of people in this activity to make it economical. And if something is not economical, I don’t think there is a need to practice it.  If sericulture is not good for certain state why should they do it? Just because a sericulture department has been created, you don’t have to waste money. Sericulture is a culture. If it is a culture for a farmer in Kolar, because he has been doing it for generations and he knows what it is. You can’t take this culture and ask a person somewhere in another state who has not even seen a silkworm, into sericulture. That’s why we have failed. There are certain practices, very native. If I have to take it to Kerala, I have to see if it is acceptable to Keralites. The family and the neighbourhood should accept it. It is a culture by itself.  

Is the silk weaving sector any better off? How well equipped is our weaving sector in catering to the needs (of high quality silk fabric) of the international silk market?

Indian textile industry is quite modern now, thanks to the Government of India interventions. More than 25,000 crores of Rupees has been infused into the industry and lot of modernisation has taken place. They are able to produce high quality yarn, a huge quantity of which is being exported. Formation of producer consortia has helped the situation by enabling the weavers to place bulk orders for raw material at competent prices. But the case has not been the same with silk weaving sector. It is too small a sector for taking to such changes. We have three sub sectors in silk weaving: handlooms, power looms and the highly organised shuttle-less loom sector. 95% of the silk fabrics produced is from the handlooms and power looms the bulk of which is coming from the handlooms. The conditions of the handloom weaver are not very good. He has no capacity to buy his raw material, which is silk yarn. He takes the yarn from a master weaver and converts it to fabric on wages. Thus he is only a converter or labourer, not an entrepreneur. The silk reeler is at least an entrepreneur. He is investing a few thousands of rupees every day. But a weaver doesn’t. So the handloom weaver is affected by the market conditions. And his situation is pretty bad. There is not enough demand for the handloom product. The reason is that he is not weaving fabric as per the requirements of the market. He knows to weave something which he continues to weave whether it sells or not. The handloom weaving industry is not reacting to market requirements.

Finally, what has been the contribution of Central Silk Technological Research Institute, to Indian silk Industry?

CSTRI has been a partner to bivoltine development, all along. Then we became the prime mover to improve quality of silk reeling. That’s where the multi end technology came into being. May be we dint succeed much in the reeling sector, because of the reasons I have already explained. But we succeeded in other areas like silk yarn dying. We successfully moved the dyers to new technology which has also influenced the market. Today the yarn dying industry has come of age. We developed a handloom and an electronic jacquard, which have diffused well in the industry. Another important development was computer aided designing coupled with a card cutting machine and automatic lacing of card. You see a large number of people using these technologies now. In Dharmavaram area itself as many as 150 computer aided design units are working. In the non-mulberry sector, the reeling and spinning machines we developed has gone to the filed in thousands, through supporting schemes. CSTRI is now recognised as a National Research Institute. It is also recognised as one of the Textile Research Associations by Ministry of Textiles, Government of India. We take up a lot of consultancy services for companies like Hindustan Lever, developing chemicals and evaluating their soaps and detergents. We have helped IFB, the washing machine people in developing a wash program for silks. We dint advocate continuous revolving of the drum. For silks, we said it should rock!

South Indian sericulture- portrait of a bygone era

Dr. Simon Charsley

An interview with K.V. Achuthan Nair, by Dr Simon Charsley, University of Glasgow

That Bangalore hosts International Sericultural Commission, is in recognition of the importance of South Indian Sericulture to global silk industry. The story, how sericulture took roots in these parts lay buried deep in history, relics sparse. What toils, earnest and selfless efforts have gone into its making! The story unfolds through this interview; conducted by Simon Charsley with K.V. Achuthan Nair (DD Seric Rtd, Department of Sericulture, Karnataka) on Friday 11 September 1992. Achuthan Nair passed away on 8^th August 2010, at 96.

To Achuthan Nair in the morning.

From Kerala originally but no family home left there: we discussed the tharavad[1] and its advantages a little.

Now 76, having retired at 55 in 1972, so must have been born 1916/ 17[2]. When he retired he thought it would be good to relax, take up some social work or some such, but people had kept coming to consult him about sericulture. They then asked him to keep the chemicals etc he was recommending so that they could get them conveniently. So he set up R.V. Enterprises[3]: they have their own product, Polmr dust[4] for grasserie and flacherie.

In 1943 he joined the Madras Department in Kollegal together with Punja[5], Ranganatha Rao[6], Venugopalan Nair[7] – 5 or 6 of them. It was hard because they had no stipend during the training period. At the time unemployment was very bad in Kerala. He knew someone in the government secretariat who    let him know about the opportunity. So it was chance that he came to sericulture.

It was the war that gave impetus to it. The British Empire had no-one else to supply silk for parachutes and they asked all states to implement projects for it. Madras put up a project for making filature silk and was given 300 basins and the filature was started. Nobody worried about the supply of cocoons, but there were only 25,000 acres - or should this have been 2,500? - under mulberry and this would be sufficient for 50 basins only. So then they got further a project for expansion of the mulberry acreage, production of eggs, research, etc.

1958 training batch of All India Sericulture Institute, Mysore
Achuthan Nair is seen sitting fourth from left

During training they were taken to Berikai just south of the Mysore border, northeast of Hosur Town in Madras, because there were a few Muslims there rearing worms on just three acres of mulberry and the Department had a small unit for purchasing cuttings from them for use in new areas. It was indigenous varieties and they were very mixed. They would just select the better bushes in the field to take cuttings from.

At Denkanikottai there was also a little rearing going on. When they went there as students during training, it was very remote, no good communications. Just one bus and because of the petrol shortage this ran on charcoal: it burnt charcoal to make gas and ran on that. No sanitary conveniences or anywhere to get food. They joked about who would be the unlucky man to get posted there. When he actually was he was asked how he felt about it. He said 'I like it, sir'. Surprised, his officer asked why: 'Because you are posting me there', he said. There was no source of food there, and he also had a problem that after he graduated he had been given charge of the family land in his own place in Kerala.

It was a sort of sacrifice they made to go to such places, but he formed a club there, the Friends Union, out of the few educated people around, in the Department and others. They used to play cards but not for gambling. They got a badminton court in the farm and in the end people started coming there on leave.

But before that A.T.Janakiram[8] was his senior officer. He had joined as a Probationer as early as 1930 and had a reputation for being very strict and difficult about allowing anyone casual leave. But he came to visit, saw him there and asked V.R. Uttaman[9] who was his immediate superior (and still living at the time), why he had not given him leave: he looked reduced and needed to go home. He replied that he could not go because he had too much to do. 'I will look after your work', said Uttaman. Of course he did not; someone else was deputed to do it, but he was very appreciative of his efforts - but he did not reward him by giving him a transfer from that place.

One particular drawback of the place was that, if there were a reduction in the cocoon rate, everyone blamed him and came and pressured him, since he was alone there. He had also to be a bit deceitful since Kollegal had to have seed cocoons every day. If left to themselves, when one man cut his mulberry others would follow, so they tended to get everyone wanting to rear at once. He would have to prevent this happening by telling them that the layings were pebrinised: if they wanted to risk it that was up to them. 'No, sir, we will wait'. The seed cocoons went by van to Kollegal at night, via Bangalore, in special cylindrical baskets. These were bamboo with gaps for ventilation and lids and they travelled on their sides, piled to allow plenty of ventilation and avoid crushing. They would get to Kollegal in the early morning.

They also started a farm in Hosur with 80 acres under mulberry, under the big Andivadi tank. Government acquired the whole irrigated area, 100 acres and it was divided into 7 units, each run independently but co-ordinated by a senior officer. It was for rearing Foreign Race (FR) seed cocoons which also went to Kollegal, and there were good selected rearers around the farm too. Hosur Cattle Farm was where the basic FR seed was prepared, i.e. it was already an embryo P system. Stock races were maintained at Coonoor, with J(apan) and C(hina) nos. There were also farms at Berikai and Denkanikote for the improvement of the indigenous race. They were therefore quite independent of Mysore, except that they would get in Mysore race from time to time as new blood, to be crossed with their own. Apart from this there was a little rearing in Hindupur which was also in Madras at the time, and there were small demonstration farms there.

Locally, 'Pure Mysore' - so termed - was being reared, very crudely. They would allow the moths to emerge from the seed cocoons, mate, and the pairs would be removed to other trays. The males would be removed; the females would lay just on the tray itself, with no disinfection. Eggs would hatch and the worms would be fed on the same tray. They would then be given to whoever required them. It was not rearing as chawki but immediate selling. Later they began using paper for laying. Another practice was to keep eggs on brass eating plates. When the worms emerged they would feed them on the plates and cover the plate with tray. This was to keep them cool, and in the coolest part of the house. After second moult they would transfer them to ordinary trays.

The price of cocoons was very low, Annas 3-4 per lb., and why sericulture continued was questioned. The answer given was that Karnataka was airconditioned, i.e. very good for worms naturally, whatever rearers did to them. There were landlords with plenty of  land, 30-40 acres under mulberry. They would go out and bring the leaf home, giving it to family members, the women, to rear. They might be taking 1000 layings for 30-40 acres, getting only 15-20 lbs per 100. The money was pocket money for the ladies, and the waste went for cattle food. The cuttings of mulberry would be stacked up like a haystack and would provide the fuel for months.

[Were tenants the rearers?] The basic idea was that it was the landlords themselves, but a portion of mulberry might be given to the poorest families on share basis. This was certainly happening then too. There was not much irrigation; most land was just rain-fed and by September the dry crops had been         harvested and there was no work for the labourers. Sericulture could provide work for the idle labourers since the mulberry would still sprout up to Jan/Feb. Rearing, it seemed, was essentially by the family. SCs[10] could not enter houses of caste Hindus so could not work in rearing there. During menstruation ladies could not touch the worms. They said they were Lakshmi and there was puja to them, especially at moulting. This was felt to be a bad time for the worms when they had to be looked after well, hence the puja. An attachment to the worms was certainly felt. [This may actually refer more to Kollegal, since he went on to say that the Hosur rearers were almost all Muslims.]

So he joined the Department after training in 1944, and was posted as Seed Campaign Officer at Hosur for the indigenous seed. His job was to expand the mulberry planted and get people rearing. In the initial stages people were very resistant, fearing some calamity in the house if they took it up. When he approached they would also ask him, what was the charitable thing in rearing? If you grow sugarcane, the thief may come and take it and we may also offer it to visitors. So there was dharma in growing it. Where was the dharma in mulberry? Of course we may get money, but we do not want to do it. So he would contact an important man and go and visit him. They would enquire about the welfare of the country, and what his sons were doing, and would go away. He would repeat such visits. Eventually he would ask him to do one thing for his sake: plant 2 acres of mulberry. He would say 'Sir, for your sake I will plant it'. So he would guide him and rear the worms as if they were his own in that man's house.

For Muslim rearers, sericulture was convenient because their ladies were not allowed to go out, but inspection was a problem. They would have to inform them in advance that they were coming, so that they could bring the worms out. But then he used to tell them that if they insisted on this he could not make them seed rearers, so they then allowed the Department people in. In fact it was identified with Muslims and they had a joking term, 'Pashadega' or some such - about which he was worried in case it implied derogatory attitudes to another community – because it seemed to be all Pashas who did it.

He was also preparing the layings and issuing them, limiting it to 100-150 per shed. He had to prepare the layings himself; he could not entrust it to anyone else because if someone missed disease, it would be he himself who would be blamed by the Department and by the sericulturists.

Kollegal was a small area and the Department there could do everything very well. In Mysore they always had big areas and a large number of rearers to contend with, and this was more difficult. He was very preoccupied about not criticising the Mysoreans: they had been good to him, so he should not do so.

He also at times had some difficulty about being a Keralan[11] and running things in Karnataka, but clearly he does have the feeling that things do not quite work properly there. The Madras officers were well trained and they had experience of everything. Everywhere the rearing was in patches of several or single villages. Even distant villages might take it up because of some marriage connection, but even neighbouring villages might not. It was a matter of personal inconvenience and convictions. He stressed that village heads were very strong in those days. If a leader did not want it done, it would not be done. He accepted also the other way round: if a head wanted to introduce it, others would follow.

A good idea to regard the rearing area as made up of villages rather than individual rearers, with clusters and isolates, e.g. the three acres at Berikai where rearing somehow managed to persist. There the rearers, who were Muslims, would reel their own cocoons on charkas. After the seed area was established, such reeling was not allowed but in practice the reject cocoons which did not go for seed continued to be reeled locally. The main centres for sericulture in Kollegal were Kuntur, Kamagere and Hanur, a little at Palya, [i.e. not a very different pattern to subsequent.]

Kuntur: there is a story that Tipu passed that side and saw it. He had heard about Kollegal silk and announced 'This is Kollegal'. [The significance of the story is not quite clear, but it seems to be that Kollegal was claimed to have been identified with silk in Tipu’s time.] There is a pond in Kuntur which was said to have absolutely neutral water which was the source of the very good colour of the silk there. It was one of the early reeling places, also Doddinduvadi and Surapura.

Cocoons were purchased by reelers who would go to the rearers’ houses, see the worms and advance money for the cocoons. The rearers were then bound to sell to them. The reeler would take a handful and put it aside 'for God', before weighing the rest and paying for them. They also charged interest on the advance. It was to avoid this kind of thing that cocoon markets were set up. The reelers were Muslims mainly.  ...  [Discussion of prominent individual reelers]....  Achuthan Nair did not know much about the silk trade. The Filature got cocoons from Mysore in the end. He thought there were small purchasers of silk in Kollegal but the big people like Rachegowda would go to B'lore. There were lots of cocoon brokers who took the cocoons to Mysore. The markets the Department set up were at Kollegal, by the filature, Kamagere and Hanur, but the cocoons from them were being bought for the filatures since there were no reelers coming to them.

Later in his career he was in charge of the silkworm gut manufacturing section at Coonoor. Ripe worms were soaked in acid and the gut was removed and stretched. Then the sericin was removed by boiling with soap. It was for external use only and was replaced with nylon, but that has disadvantages: people may be allergic to it and it snaps, neither of which happens with silkworm gut. Previously it had been produced in Spain by ladies incubating the cocoons under their breasts and exported to Johnson & Johnson in London: a complex and extraordinary tale in fact here. He also tried to develop gut for fishing as it is undetectable in water, and even to make brushes out of the waste, but the operation had to be closed.

Farewell to KV. Achuthan Nair, from All India Sericulture Institute,
on  31.03.1960 Mr. Nair is flanked by MN. Narasimhanna
on his right and NK. Guruprasad (Principal) on his left

1948-53 he was at the Hope Silk Farm in Hosur for FR production, and in 1956 when Kollegal joined Mysore he was Sericultural Superintendent in charge of the Central Grainage there.

Their separate organisation continued for some time. He then went to CSB as Sericultural Expert in the All-India Sericultural Training Institute here in Mysore. At the time research was still at Channapatna under the State government, but he was starting it at the Institute. All the sericultural processes had to be organised there and he trained two batches. They came from all over India and are now in good position everywhere.

He would have been happy to continue there but he had not had experience of serving in Karnataka. Had been in Madras [Hosur and Kollegal] with its different atmosphere: competitive and with the opportunity to have experience of all stages of sericulture. Uttaman became Director at this time. He called him and told him that there were vacancies at Chamarajanagar, Kolar and? Channapatna: which did he want? He said he wanted to go where he could best show good work. So Uttaman told him to take Chamarajanagar. There had previously been no organisation there and he had to establish everything. It also had the hill station at BR Hills and Uttaman thought his experience at Coonoor would be useful. So he organized the division. This was in 1960. He had to give technical advice to the villagers and there were farms to be opened. He wanted to purchase the land there where the Farm/and grainage are now, but the 21 or 25 Uppaligashetty landowners were not willing to part with it at the rate of compensation offered. ... [Account of obtaining land there, told off the record, apparently because it implied criticism of what went on in Karnataka.]  ... . He was in charge of 3 taluks and had also to start chawki rearing there. The rearing at the time was by very crude methods and the object of the centres was to demonstrate better. For each there was a demonstrator and a labourer, supposed to be supervised by a committee of sericulturists. The committee was expected to lease mulberry land for the use of the centre but sometimes this was not possible. Then the farmers would have to bring in the leaves to feed their own worms. Maybe ten people would bring leaves from ten different gardens: that was not good as they tended to get mixed up in the feeding. If the committees had worked well, Chawki Rearing Centres (CRCs) – would not have turned out badly.

Sericulture was always a side industry. The poor man can't afford to produce a successful crop because of all the drawbacks he labours under in the form of shortage of resources. And for the rich man, he has other diversions, so is less interested. They used to consider sericulture as a poor man's industry, but just recently it has turned into a richman's.

Markets: along with the CRCs they were opening cocoon markets in Chamarajnagar. The first idea was that should be one within 5 miles of every rearer, so that he would be able to get there easily. They would have 4/5 reelers present for auctions and they would be forced to attend. But then the reelers would not come: suppose the rate was lower in some other market, they would want to go there. And rearers similarly. It was not possible to control it by legislation. A rearer went to court arguing that he had produced the cocoons and should be able to sell where he pleased. So they retained the markets where transactions were good, but in the end could not force people to use any particular one. Finally few survived but the big ones, and more people go to Ramanagaram. [So what about small markets like Harave and Hanur that still existed?]  They were big markets earlier and still have some people wanting to sell only there. Harave was at a centee of rearing. Nearby is Maliyur with MLA[12] M.C. Basappa whose brother M.C. Swamy was a very good rearer from the beginning. He was an Agriculture graduate and used to take 400-500 layings and rear continuously. He is one of his customers for chemicals.

After the War there was a setback. Imports began and a tariff of 150% was imposed to maintain the home industry. It was sericulturists’ capacity to make use of idle labour which interested government, safeguarding the interests of labour. Indian silk was costly, hence the need for protection.

Killing silkworms: In Berikai there was a Tamil family, Gowdas, Mariswamy & Co. They were vegetable seed preparers and suppliers. They were good agriculturists and friends of his, and they used to attend his functions. He requested them to plant mulberry, but for all of 32 years’ friendship they resisted. They asked him not to press them. And it was the connection with killing worms which worried them. So there were some people who did think like that. A story of an orthodox Brahmin lady in Madras: when she saw a boy in charge of reeling she asked him what community he belonged to. He said he was an Iyengar Brahmin. She: ‘Why, being born as a Brahmin, should he do such a cruel action? Is it not sinful?’ Then seeing some silk fabric, she immediately wanted it. So the boy wanted to know, was that not sinful too? She: that it was different’.

The purity of silk: Pithambara = 'yellow silk' and it is mentioned in the Puranas as being used by the Gods. [Why?] Because silk is a non-conductor of heat and electricity. So even now Brahmins used to wear silk only. For worshipping, they didn't allow the pupa to be killed. Ripe worms are put on a plate and allowed to roam around producing silk. Maybe 5-6 and they move about the plate forming a sheet of silk, and this sheet is used to keep the idol on in old Brahmin homes. He himself clearly feels that it is a somewhat illegitimate betrayal of the silkworm to steal its cocoon and destroy it in the process, a creature dependent on man. But nowadays nobody has any such sentiments anymore.

Sericulture before Tipu. There were no sources for this. [This led him to stress how] in the 1940s there was no book to refer to for sericulture. Even when he was the sericulture man in the Institute he had to note down everything for himself. All aspects of science come together and interact in sericulture. He would discuss points that occurred to him with the specialists in Botany etc. [In fact there was already some good Indian literature, e.g. N.G.Mukerji’s Handbook of Sericulture of 1910/11, N. Rama Rao and M. Yonemura’s on silkworm rearing of 1925, Maxwell-Lefroy’s Report of 1916/17, On the Silk Industry of India, and others; but none have been easy to find.]

Any new people wanting to take up sericulture come to contact him. They come with grand notions of starting with 20-50 acres: he tells them to plant 2 acres for a start. Can then continue rearing from that and know all the pinpricks of sericulture. Then they can expand. If you fail after plunging in, you will fail really badly. His contribution he sees as increasing yield by 1 kg. He did have a scheme after retirement to set up a grainage and farm, get in other retired people to establish a consultancy service, but there were problems in getting a grainage licence etc, so he settled down with just himself and consultancy. The only thing is that he cannot go and visit the farms. If he went to one, he would have to go to all and that is impractical. But he does see private consultancy as the way the industry has to go.

He is also keen on people setting up local sericulture organisations, with their own grainages etc, on the Japanese model. [I commented that in the 1920s there had been so much talk of conferences and associations and that kind of thing, but it had gone away. Why were things different now?] He thought it was because there were so many more educated sericulturists now that it is increasingly possible to organise. Such a scheme with which he is associated - confidential - was now under application.

[Individual contacts:  ... .]

He was also in the Seed Area for 5 years as Assistant Director in charge of the whole thing: in these days there are so many Deputy Directors and a Joint Director and still it does not run properly. He noted that it was cyclical, every 5 years. In 1965 there was talk of pebrine but with the co-operation of his staff they could easily control it. Responsibility is the thing. [I put it to him that in the early stages of the industry Brahmins had played a big part, subsequently Lingayats had been very important.] He agreed and also that this had something to do with the idea of service they had. Subsequently people just in it as jobs and not really interested. [The way things were running down was an inevitable theme, but there was also a very positive side to his account.]

[Mr Nair was, as seen above, a very interesting informant, a charming man as well. It was a pleasure to spend time with him, his delightful smile animating an otherwise aging face.]

Editors Notes

[1] Tharavad: name of the joint family of Hindus in Kerala. The Nair tharavad used to be a complex house hold with unique joint family lifestyle, now almost nonexistent.

[2] Achuthan Nairs’s son, Krishnan Unni confirms that Mr. Nair was born in February 1917 in a village called Cheramangalam in Palakkad district, Kerala State, South India. Having lost his parents at an early age, he grew up under protection of relatives and graduated from Annamalai University in Science (a rare achievement those days).  

[3] RV Enterprises: Achuthan Nair set up his company together with Mallaraja Urs, Assistant Director Sericulture. R in the name came from Ratna Urs (Mrs Urs) and V from Valsala (Mrs Nair) - Reported by Sivakumar, Mr. Nair’s son.

[4] Krishnan Unni reports that the name ‘Polmr’(pronounced as ‘polmer’) was coined by Mr. Ravi Varma, a friend of Achuthan Nair, and then Area Manager of Kerala Soaps & Oils Limited (now Kerala Soaps), a state owned soap manufacturing company. Mr. Ravi Varma’s daughter Samyukta Varma is a well known Malayalam film actress. Both sons think that the rather strange name was created by combining the first letters of various chemical constituents of the powder. However they aren’t sure what these chemicals were.

[5] Former Deputy Director, Department of Sericulture, Karnataka

[6] Former Project Coordinator, National Silkworm seed Project, of CSB

[7] Former Director, Department of Sericulture, Karnataka

[8] Former member Secretary of  CSB. He was instrumental in the foundation of Department of Sericulture, Uttar Pradesh.

[9] Former Director, Department of Sericulture, Karnataka

[10] Scheduled Caste: The Indian constitution recognizes list of scheduled castes and scheduled tribes eligible for various reservations on account of their socially deprived status.

[11] One hails from the southern state of Kerala, and speaks Malayalam; commonly called Malaylee.

[12] Member of (state) Legislative Assembly.

READ A PREVIOUS STORY BY Prof. CHARSLEY

Contact Prof Charsley: simoncharsley@yahoo.co.uk
Acknowledgements: We thank Mr. Krishnan Unni, CSR&TI, Mysore, to whose collections the two photographs belong and Mr. J. Justin Kumar, CSR&TI, Mysore who made available the scanned images. We are indebted to Mr. M.N.S.Iyengar, Joint Director, CSB (Retd) who (over telephone) shared some interesting information regarding individuals whose names appear in the text. This info is used in editor's note

TEMPERATURE STRESS INDUCED TRANSCRIPTION AND ITS POSSIBLE APPLICATION IN SILKWORM BREED IMPROVEMENT.

The mulberry silkworm (Bombyx mori L.) is one of the most thermal-sensitive organisms. Intensive and careful domestication over centuries has apparently deprived this taxon of opportunities to acquire thermo tolerance. This vulnerability is more pronounced in bivoltine races compared to polyvoltine ones. Thus, among many factors attributed to poor performance of the bivoltine strains under tropical conditions, the major one is lack of thermo tolerance. Many quantitative characters decline sharply at higher temperatures. Therefore, one of the key considerations in developing bivoltine hybrids for tropics could be need for thermo tolerant bivoltine races. This could be achieved through hybridization of polyvoltine with bivoltine races which is a prolonged and tedious procedure mainly due to the delay in fixation of economic characters. In India earlier efforts in this direction using Pure Mysore, a comparatively robust but poor silk yielding Indian race did not yield expected outcome which pointed out that- economic cocoon traits were negatively correlated with high temperate resistance (Tazima & Ohnuma, 1995). The recent advances in silkworm breeding and those in stress induced protein synthesis have opened up new avenues to evolve robust productive silkworm hybrids. 

The Phenomenon of Heat Shock:

Heat shock is nothing but a thermal injury caused by sudden increase in temperature in biological molecules like DNA, RNA, lipids, etc., of the cell which are vulnerable to heat stress. This leads to a number of abnormalities at cellular level. Normal pattern of protein synthesis halts. Transfer RNA and ribosomal RNA loose conformational integrity leading to degradation. DNA looses ability to function properly. There is aggregation of intermediate filamentous proteins at the nucleus instead of forming the cytoskeleton. At the same time pH of body fluid also drops. Increase of temperature leads to increase in kinetic energy of macromolecules, decrease of ionic bonds, hydrogen bonds, Van - der - Waals bonds etc., and increase its hydrophobic interactions; leading to loss of its shape. Denatured proteins also get adhered to DNA and restrict enzymatic access to DNA causing large-scale DNA damage. The heat shock thus ultimately leads to death of cells. 

Another most important effect of temperature (or stress of any kind) is on cellular proteins by unfolding them. Cellular proteins are typically folded in their native conformations while functioning in cells. They unfold at the following contexts: 1) during de novo synthesis of polypeptides and assembly of multimetric proteins; 2) during intra cellular transport and organellar import when a protein must unfold or remain unfolded to cross the boundary of a cellular compartment; 3) during or after exposure to a protein denaturing stress. At these times unfolded proteins may be susceptible to inappropriate interactions with one another or with other cellular components. More over once unfolded, a protein can prospectively interact with folded proteins and induce them to unfold. Such interactions can result in aggregates of unfolded protein that at best diminish the pool of functional proteins and at worst are cytotoxic (Feder, 1996). 

However, a brief exposure of cells to sub-lethal high temperature was found to render protection to the organism from subsequent and more severe temperature. In a study with heat shocked Drosophila subobscura Digley and Smith (1968) reported continued survival and acclimatization of the experimental insects at higher temperatures. 

Heat Shock Proteins:

It was Ritossa (1962) who reported that the metabolic inhibitor dinitrophenol and heat induced a characteristic pattern of puffing in the chromosomes of Drosophila. It was observed by the author that when Drosophila larvae were shifted from 27°C to 37°C temperature similar puffs appeared in the polytene chromosomes. This discovery eventually led to the identification of the heat-shock proteins (Hsp) or stress proteins whose expression these puffs represented. By the mid-1980's, investigators recognized that many Hsps function as molecular chaperones. The word chaperone (pronounced as 'sha-pə-"rōn) means ‘an older person who accompanies young people at a social gathering to ensure proper behavior; broadly: one delegated to ensure proper behavior’. Molecular chaperones work more or less in a similar fashion. They are a class of proteins that enable the cell to cope with the problem of protein unfolding subsequent to a stress. Chaperones can recognize and bind to the exposed side groups that charecterise unfolded proteins. In so doing molecular chaperones prevent the bound side groups from engaging in inappropriate interactions with other cellular components, as well as stabilize the bound proteins in an unfolded state. Alternatively, chaperones can target bound proteins for degradation or removal from the cell. The constitutively expressed heat shock proteins (heat shock cognates) perform these roles for nascent polypeptides or proteins that unfold during normal cellular processes, while the inducible hsps function in response to the protein denaturation due to stress.

A summary of the mechanism for expression of heat shock proteins within a cell is given by Kregel (2002) as follows. ‘Heat shock factors (HSFs), present in the cytosol, are bound by heat shock proteins (HSPs) and maintained in an inactive state. A broad array of physiological stimuli (“stressors”) are thought to activate HSFs, causing them to separate from HSPs. HSFs are phosphorylated by protein kinases and form trimers in the cytosol. These HSF trimer complexes enter the nucleus and bind to heat shock elements (HSE) in the promoter region of the Hsp gene. Hsp mRNA is then transcribed and leaves the nucleus for the cytosol, where new Hsp is synthesized’. 

Subsequently, every form of stress is known to induce these proteins in all tested organisms from bacteria to man. Inducing stresses include ethanol, heavy metals, hypoxia, hyperoxia, changes in pH, free radicals, various poisons and toxins, ischemia, osmotic shock, ionizing radiation and many others (Feder, 1996). Thus the term “heat shock protein” is a bit of a misnomer, and it is more accurate to refer to these proteins as “stress proteins”. Yet the term heat shock proteins is so deeply entrenched in the literature and so accurate a descriptor of the response at high temperature that, it is likely to persist for years to come (Denlinger and Yocum -1998).

Heat Shock Proteins (HSP) – Types and functions:

Heat-shock proteins are classified into families on the basis of sequence homology and typical molecular weight as Hsp 110, Hsp 100, Hsp 90, Hsp 70, Hsp 40, Hsp 10 and small heat- shock protein families. In eukaryotes many families comprise multiple members that differ in inducibility, intra cellular localisation and function which are presented briefly in the following table:-
                                                                        [click to enlarge the table]

(After Moseley, 1997)

The threshold temperature for Hsp induction is correlated with the typical temperature at which species live. Thermophilic species have a higher threshold than the psychrophilic species. Many species exhibit characteristic and distinctive patterns of Hsp expression (or non expression) during the various stages of development, including gametogenesis, embryogenesis and metamorphosis. Extensive studies have been conducted on the heat- shock response by a large number of workers across the world in a variety of insect species such as Drosophila sp. (Tissiers et.al., 1974; Lindquist, 1980, Gilchrist & Huey 1999; Karunanidhi et al, 1999), the locust Locusta migratoria (Whyard et al., 1986) Anopheles stephensi (Nath and Lakhotia, 1989), the tobacco hornworm - Manduca sexta (Fittinghoff and Riddiford 1990), the fleshfly-Sarcophaga crassipalpis, (Joplin and Denlinger 1990), Lymantria dispar (Denlinger et al., 1992). Studies examining stress protein expression in the wild or in response to laboratory stimulations or of natural stress regimes are still few. Nonetheless, even these few studies are sufficient to demonstrate that patterns of stress protein expression can be correlated with specie’s natural thermal environments; that is, cells and species from warm environments undergo a stress response at warmer temperatures than counterparts from cool environments (Lindquist, 1986; Huey& Bennet, 1990; Sarge et al., 1995; Somero, 1995). Numerous studies have now demonstrated that heat shock proteins are responsible for a large component of inducible thermotolerance (Morimoto et al., 1994). Studies in which hsp genes were either removed or their expression inhibited demonstrate a reduction in inducible thermotolerance (Sanchez and Lindquist, 1990; Craig and Jacobsen, 1984; Johnston and Kucey, 1988). Likewise the insertion of extra copies of the hsp70 gene increased thermotolerance in both cells (Li et al, 1991; Solomon et al., 1991; Li and Duncan, 1995) and whole organisms (Welte et al., 1993; Feder et al., 1996). 

The quest for heat tolerant silkworm breeds.

Among many factors attributed to poor performance of the bivoltine silkworm strains under tropical conditions the major aspect is that many quantitative characters decline sharply when temperature is higher than 28°C. The risk of hybridization of polyvoltine to bivoltine could not be taken due to the delay in fixation of economic characters. The long and hard struggle to evolve robust-productive silkworm hybrids has not so far met with satisfactory results. Veteran silkworm geneticist Y. Tazima made one of the first attempts in this direction. He started a breeding experiment by using Pure Mysore and C134a as parent breeds, but did not yield expected outcome. Prof. Tazima concluded with an apprehension whether the heavy cocoon trait was negatively correlated with that of high temperature resistance (Tazima and Ohnuma, 1995). The only way out was to evolve tropical bivoltine breeds. In this direction a breeding technique was evolved at CSR&TI, Mysore, to select the robustness genes along with its modifiers in high temperature conditions. Consequently in 1988 a temperature tolerant bivoltine hybrid namely CSR18 X CSR19 was developed and authorized for commercial exploitation (Sureshkumar, et.al., 2002). Though the introduction of CSR18xCSR19 in the field for commercial rearing during summer months was seen as a big success, the productivity level and returns realized did not match to that of other productive CSR hybrids. Therefore, the acceptance level of this hybrid among farmers was not up to the expected level. 

As conventional breeding experiments encounter bottlenecks the silkworm breeder is bound to look for other possible options as molecular marker assisted breeding and transgenesis breeding. In spite of remarkable progress achieved in the disciplines of silkworm genomics, silkworm genetics, silkworm biotechnology and silkworm breeding no much result have been forthcoming in evolving temperature tolerant bivoltine silkworm breeds. Probably the reason for this lies in the fact that such a breed is largely the requirement of countries in the tropical sericulture belt as India, where interdisciplinary research is yet to materialize in its true sense. 

Heat shock proteins – a missing link in silkworm breeding for robustness

Though there are reports on the activity of heat shock proteins in silkworm, the body of literature available on the molecular mechanism of temperature sensitivity and heat shock response in silkworm is rather thin as compared to the enormous work done on other insects. Evegnev et al., (1987) studied heat shock response in Bombyx mori cells and found that temperature elevation induced active transcription of heat shock mRNAs in infected cells. But at the level of translation heat shock treatment failed to induce Hsp synthesis and was not able to inhibit production of polyhedrin in such cells. Joy and Gopinathan in 1995 reported the appearance of 93, 70, 46 and 28 kDa protein bands consequent to high temperature exposure in Bombyx mori. in both bivoltine and multivoltine strains, but with varying kinetics. The isolated hemocytes of multivoltine race exhibited the induction of 70 kDa protein. Lee et.al., in 2003 cloned a genomic DNA fragment containing a promoter region for the gene encoding an HSC70-4 homologue, the structure of which was deduced from the partial cDNA sequences that were registered in a Bombyx mori EST data base. The deduced amino acid sequence with 649 residues was 89% and 96% identical to those from Drosphilla melanogaster hsc-4 and Muduca sexta HSC-70-4 respectively. The expression analysis by reverse transcription PCR demonstrated that mRNA transcription occurred in all tissues examined and was not stimulated by heat shock. Thus HSC70-4, the molecular chaperon is ubiquitously expressed in every tissue of Bombyx mori. In a recent study Vasudha et.al., (2006) observed differential expression of hsps in silkworm strains. 90 kDa in the first, second and third instars, 84 kDa in the fourth instar and 84, 62, 60, 47 and 33 kDa heat shock proteins in fifth instar was observed in response to heat shock. Use of Heat shock proteins as molecular markers for evaluation and evolution of thermotolerant silkworm strains has been suggested by them.

Considering the enormous investigations conducted on HSPs in a plethora of organisms ranging from bacteria to man, it is felt that there is an acute shortage of literature on the heat shock response of the silkworm Bombyx mori. However, the literature available on the heat-shock protein synthesis in other lepidopteran insects suggest that there is much scope for similar studies in silkworm HSPs in detail with the set target of harnessing the genes responsible for rendering thermo-tolerance in hardy polyvoltine that can be transferred in bivoltine breeds since high temperature resistance is recognized as heritable character in silkworm (Kato et al., 1989). In order to achieve greater success in this regard, there is dire necessity for (1) Understanding the molecular mechanism of temperature tolerance in silkworm; (2) Identification of the various families of HSPs synthesized and the threshold temperature, which induce their expression; (3) Understanding the differential expression pattern of various HSPs in bivoltine and polyvoltine races; and (4) To locate the genes responsible for the heat inducible HSPs and subsequent steps to introgress the same into the silkworm genome either by conventional breeding or by use of molecular techniques. The recent success stories in silkworm transgenesis (Tomita et al., 2003) shed rays of hope in this direction.

References:

Craig, E.A., and K. Jacobsen. 1984. Mutations of the heat- inducible 70 kilodalton genes of yeast confer temperature-sensitive growth. Cell 38:841-849.

Denlinger DL and Yoccum GD (1998). Physiology of Heat Sensitivity in Insects. In: Lethal Temperatures in Integrated Pest Management. Eds: GJ Hallman and DL Denlinger. Westview Press, Boulder Co., pp:7

Denlinger DL, Lee RE, Yocum GD and Kukal O (1992). Role of chilling in the acquisition of cold tolerance and the capacitation to express stress proteins in diapausing pharate larvae of the gypsy moth Lymantria dispar. Arch. Insect Biochem. Physiol., 21:271-80.

Dingley F, Maynard Smith J (1968). Temperature acclimatization in the absence of protein synthesis of Drosophila subobscura. J. Insect Physiol., 14:1185-94.

Evgenev MB, Braude-Zolotareva TY, Titarenko EA, Levin AV, Denisenko ON, Ulmasov K and Karaev K (1987). Heat Shock response in Bombyx mori cells infected by Nuclear Polyhedrosis Virus. Mol. Gen. Genetics, 215:322-325.

Feder. M. E. (1996) Ecological and evolutionary physiology of stress proteins and the stress response: the Drosophila melanogaster model. In Animals and Temperature: Phenotypic and Evolutionary Adaptation to Temperature Eds. IA. Johnston and A.F. Bennett, Cambridge University Press. pp.79-102

Feder, M.E., N.V. Cartaño, L. Milos, R.A. Krebs, and S.L. Lindquist. 1996. Effect of engineering hsp70 copy number on hsp70 expression and tolerance of ecologically relevant heat shock in larvae and pupae of Drosophila melanogaster. J. Exp. Biol. 199:1837-1844.

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