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Introduction
The capsularis varieties cover 60 per cent of the jute area, whereas the olitorius varieties cover 40 per cent of the area, mostly in the southern West Bengal. ‘JRC 321’ (Sonali) has a light coppery-red stem. It is suitable for low-lying areas for early sowing from late February to mid-March. It comes to 50 per cent flowering in about 125 days (variable); it is fast-growing and has good-quality fibre. It yields 20-25 g per hectare in northern West Bengal and Bihar. ‘JRC 212’ (Sabuj sona). This variety has a full-green stem. The sowing time is from late March to mid-April. It is suitable for medium and highland where inundation does not occur. It is particularly good for Assam, Bihar, northern West Bengal, Uttar Pradesh and Orissa. With 60 kg N per ha, it yields around 30 q per ha. ‘JRC 7447’ (Shyamali). This variety has a full-green stem, and is an X-ray derivative of ‘JRC 212’. It responds better to higher doses on N above 60 kg per ha; it is suitable for Orissa, Nadia, Murshidabad and 24-Parganas. ‘D 154’. It is an old standard variety, originally selected in 1918 from ‘Kakya Bombai’. It is a hardy variety and can adapt itself to all conditions. It yields 20-25 q per ha. ‘JRC 1108’. A pre-release variety. It yields better than ‘D 154’, equaling ‘JRC 212’ at places, and is fairly resistant to stem-rot and root-rot. ‘JRO 632’ (Baisakhi tossa). This variety has a full-green stem; its sowing time is from 15 April onwards on midlands and highlands. It takes 130-140 days to flower; its seed colour is steel Grey; its yield potential is 40 q per ha; its yield average 32 q per ha with 40: 20: 40 NPK plus farmyard manure. Its fibre is of good quality. ‘JRO 878’ (Chaitali tossa). The stem of this variety is red-pigmented. Its sowing time is the second week of March of mid-April only on highlands. It is non-lodging and has non-shattering pods. It does not flower prematurely. It is suitable for West Bengal and Orissa. Its yield potential is 38 q and the average yield is 32 q per ha with 40 N: 20 P: 40 K plus farmyard manure. ‘JRO 7835’ (Basudev). The stem of this variety is green. It is sown in early March to early May. It is non-lodging and bears non-shattering pods (It does not flower prematurely. It is suitable for all areas with highlands). It is high-yielding and produces around 34 q per ha with 40: 20: 40 NPK plus farmyard manure. ‘JRO 620’. The stem of this variety is red-pigmented. It yields fibre of superior quality. It yields 3-4 quintals less than ‘JRO 632’ and, therefore, has gone out of cultivation. ‘C.G.’ (Chinsurah green) gives a poor yield and has been with drawn. The pre-release variety ‘JRO 524’ (Navin) yields as high as, or more than ‘JRO 7835’, with added qualities of fine fibre and a stem that rets quickly. According to the Department of Agricultural Research and Education, ICAR, Government of India, in 1999-2000 the following varieties have been identified / released. (i) JRO 2345 was identified as a promising strain of jute with high degree of resistance to premature flowering even in early March sowing. Some genotypes of jute suitable for paper pulp production identified are JRO 66, JRO 3690, OIJ 254 (Non Soong), JRO 878 and OIN 205 among C. olitorius and JRC 321, PBC 6, Hybrid CJRC 4444, Vidyasundar and Halmahera among C. capsularis. These varieties / culture produced high biomass and gave more than 80% pulp yield when harvested after 120 days.
The defects in the fibre are its being barky and croppy (incomplete submerging) or incomplete retting ; specky (apion damage) ; leafy (incomplete retting or washing) ; and sticky (defective extraction). The fibre becomes dirty by using clods of earth and muddy retting water and careless washing. The plants become mossy with adventitious roots emerging from the stems. The fibre becomes shyamla as a result of iron-tanning reaction. ‘Roots’ are caused by more than one factor but the main one is ‘incomplete separation of fibre at the base of the stem during retting’. The quality of the jute fibre among varieties differs on the basis of anatomical features of the fibre cells and their orientation and is genetically controlled. Coarser and light-body fibre is obtained from sandy soils whereas clay-loam soils with silt give fibre of superior quality. Climate and the nutrition pattern also affect the fibre. But the most important single factor is ‘retting’ which, if faulty, mars the positive contributions of the variety, soil, climate etc. Under-retting gives coarse and over-retting dazed and weak fibre. Grading system for white jute (capsularis) has 8 classes, viz. W1 to W8, on the basis of length, strength, fineness and lustre, and freedom from enlargement and ‘roots’ (rejectable balas portion). For Tossa jute (olitorius) there are 8 classes, viz. TD1 to TD8. Weeding, especially in the early stage, is a must. For a broadcast crop, the pre-sowing application of 2,2,3,3 tetrafluorpropionate of sodium proved to be beneficial. A post-emergence application of mono-sodium methanarsonate with or without 2,2 dichloropropionate, as a directed spray, proved to be beneficial in row-cropped fields. Yields, with two hand-weeding, however, are significantly superior and constitute the prevailing standard practice. Smothering the weeds between rows with a wheel-hoe saves labour and helps to mulch the soil. According to the Department of Agricultural Research and Education, ICAR, Government of India, in 1999-2000, various weed-management practices, viz. Standard animal weeding, chemical weeding, farmers’ practices and pre-emergence chemical application followed by manual weeding were evaluated. Application of Fluchloralin @ 1.0 kg/ha as pre emergence herbicide followed by one manual weeding at 4-5 week crop age gave comparable fibre yield (2.8 tonnes/ha) in jute as compared to completely weed free condition. This weed management was superior to prevalent farmers’ method viz. 2 or 3 weeding, as and when required between 2 and 6 weeks of crop age. The female of jute apion (Apion corchori Marshall) lays an egg at a node where a knot is formed ; it makes one puncture or several on the same plant. The jute semilooper (Anomis sabulifera Guen.) eats the tender leaves and is widespread ; it usually comes in three waves between late June and August. The yellow mite (Hemitarsonemus latus Banks) sucks the sap from young apical leaves which curl, and the growth of the plant is arrested. The hairy caterpillar (Diacrisia obliqua Walker), when young, is gregarious on a single leaf and later scatters out and feeds on the foliage. The root-knot nematode (Meloidogyne incognita Kofoid and White) attacks the capsularis varieties more than the olitorius varieties and induces chlorotic symptoms and bunchy top in extreme cases and arrests growth. What is most important is that it provides foci for root infection by the fungus Rhizoctonia batarticola (Taub.) Butler. The burrowing cricket (Brachytrypes achatinus Stoll is a menace to seedlings which are cut. The pest is mostly confined to Assam. The indigo caterpillar (Laphygma exigua Habn.), the leaf-miner (Trachys dasi Thery.), the red mite (Olygonychus cofeae Neitner), the jute stem-girdler (Nupserha bicolor postbrunnea), and the leaf-eating weevil (Myllocerus discolor Boheman) are not of commercial importance. It has been found that DDT and Gammexane, with a limited efficacy in the field, are unprofitable. Ethy1 parathion and Endrin are highly efficacious against all major pests. But because of their hazardous nature, they have been withdrawn. Endosulfan, Leptophos, Phosalone, Fenitrothion, Chlorfenvinphos are effective to different extents against the major pests; Monocrotophos and Tamaron on semilooper; lime sulphur on yellow mite and Heptachlor and Aldrin dust on crickets and Dicofol on red mite, are effective. The important diseases of jute are
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