Abstract
Future of raw jute fibre consisting of Corchorus and Hibiscus species lies mainly through quality improvement for diversified and value-added uses. This can be achieved in three broad ways, viz. (1) technical processing, (2) genetic manipulation, and (3) cultural along with retting practices. The paper presents following a brief discussion on the role of fibre quality improvement for various diversified products, the factors influencing quality parameters, their limitations in applications, and future thrust areas.
Commensurate with the expected rise in production of jute and kenaf by 3-4 times in 2050 of the present value there is a need for proportionately higher attention for improved yarns to meet product specific quality norms for the manufacture of (i) high quality blended apparel grade textiles, (ii) Technical, industrial and home textiles including non-woven, (iii) automotives, (iv) soil savers, (v) bio-composites, (vi) pulp and paper, (vii) fine chemicals, cosmetics and healthcare products, and (viii) bio-fuels. Technological upgradations are required for meeting the prescribed limits with consistency in quality.
Improvement in fibre quality either genetically or by improving technological processing, or through improved cultural practices is of prime concern. This will enhance the demand for jute yarns. We generally concentrate on improving texture, colour, weight per unit reduction, hairiness, low extensibility, poor abrasion resistance, etc. in order to improve the quality. The principal uses for jute yarns are for industrial purposes in which adequate strength is normally regarded as essential. Appearance, colour and other attributes are however of relatively lesser significance. It is now regarded that the yarn should be of finer counts (6 lb/ spy and below) which should be not only quality- but also cost-competitive so as to attract the market. On the other hand, such yarns should be converted to light, dense and strong hessian fabrics for ready acceptability to the market and higher financial return. This is a technological challenge for those engaged in industry to achieve the above targets.
From plant anatomical point of view the length-breadth ratio (L:B) of ultimate fibre cells has a definite bearing on fibre quality. Higher the ratiofiner is the fibre.
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1Present address: 2/74 Naktala, Kolkata, West Bengal, India, PIN 700 0047
Some wild species have been identified as prospective donors to impart higher L:B
ratio vis-a-vis finer fibre through appropriate breeding practice. Similarly, there are someotherwild species which mayalso impart finer fibrequality. High lignin content in these fibres is responsible for colour instability, which is a distinct disadvantage in the dyed products. Reducing lignin content to the optimum level by genetic manipulation is, therefore, logical. Detailed studies on a jute mutant, ‘deficient lignified phloem fibre’ (dlpf), suggested its usefulness to engineer low-lignin jute variety. Genetical manipulation is a very important approach to achieve the targeted quality improvement. Assemblage of genes on the jute chromosomes is very poorly understood. It is now necessary to focus on developing linkage map of olitorius jute, in particular, to start with, which would help in preparing an integrated map using molecular map data on the species. In kenaf, cytological studies of various inter-specific cross derivatives established the genome constitution of H. cannabinus L., a diploid, indicating a genomic relationship between this species and H. radiatus L. H. sabdariffa L. is, however, an autotetraploid. It is extremely important to make note of the fact that modern biotechnological methods and tools in combination with traditional approaches through marker assisted selectionhave the potential to achieve product specific quality improvements in future calling for international network of activities as happened in few other crops, mainly cereals.
Improvement of cultural practices, particularly retting, is considered another very important approach, which should be user-, cost-, as well as environment-friendly, for quality upgradation of the fibres for both these crops.
In terms of constraints to achieve the targets stated above it is imperative, from technological point of view, to develop some suggested machineries and quality monitoring instruments, and, from the point of view of plant research, adequate fund and international network activities for studies on jute and kenaf genome with well-targeted programme.
Introduction
Favourable conditions for jute cultivation are found in the deltas of the great rivers of their tropics and sub-tropics - the Ganges, the Irrawaddy, the Amazon, and the Yangtze, for example, where irrigation, often by extensive flooding, and alluvial soils combined with long day lengths prevail. The crop however thrives very well under rainfed and hot humid and sub-tropical conditions in the Bengal Basin in India and in Bangladesh where more than 80 % of the crop of the world is grown. Comparatively, kenaf requires less water to grow than jute and is now grown in several countries in Europe, Africa, South America, Mexico, the United States, Japan and China. Both jute and kenaf reach 2.5-3.0 m in height at maturity; but kenaf, although still requiring a longer day length for vegetative growth, flourishes in drier conditions than jute can, and can adapt to a wider variety of soils and climates. As a result, it has often been preferred to jute as a fibre crop by many countries in Africa and Latin America, although usually for internal consumption. Significantly, kenaf (H. cannabinus) plantation (if grown in high density) has been recorded to fix about twice the amount of CO2 as compared to forest plantation thereby contributing to global and regional environment (Lam et al., 2003).
The specifications and standards of classic jute products have remained unchanged for decades. The traditional products are dominated by sacks (nearly 50 %), though improved ‘food bags’, devoid of mineral oil, meant for cocoa and coffee beans have been developed out of these sacks. Next is hessian (< 20 %), yarn for carpet & twines (≈ 20 %), hessian for CBC (≈ 2 %), and other items including soil savers, jute woven matting, bags, decorated farics, etc. (≈ 10 %). Commensurate with the expected rise in production of jute and kenaf by 3-4 times in 2050 of the present value there is a clear need for proportionately higher attention to non-traditional diversified products. It is prudent that for jute industry to survive and possibly flourish with a much brighter future it should take recourse to this non-traditional group of products which will require generally the improved quality fibres. The product specificities of a variety of these products have been documented (Hazra and Karmakar, 2004; Karmakar et al., 2008), but needs lot more work for refining for each area of application. The manufacture of diversified jute products requires the use of best grades of raw jute in most cases, more capital investment, higher textile levels of design and market skill, more capable and focused mill management, a degree of entrepreneurship above and beyond that usually found in the traditional industry, and on the top of that, considerable R&D expenditure. The real future, however, lies in the area of technical textiles (Roy, 2008).
The improved yarns are needed to meet product specific quality norms for the manufacture of (i) high quality blended apparel grade textiles, (ii) Technical, industrial and home textiles including non-woven, (iii) automotives, (iv) soil savers, (v) bio-composites, (vi) pulp and paper, (vii) fine chemicals, cosmetics and healthcare products, and (viii) bio-fuels. Technological upgradations are required for meeting the prescribed limits with consistency in quality also. This can be achieved in three broad ways, viz. (1) technical processing, (2) genetic manipulation, and (3) cultural along with retting practices. The paper presents following a brief discussion on the role of fibre quality improvement for various diversified products, the factors influencing quality parameters, their limitations in applications, and future thrust areas.
