Effect of planting geometry on leaf yield and quality of mulberry chawki garden A. GHOSH, T. DUTTA (BISWAS), A. K. SAHA, SHIVNATH, N.B. KAR, K.MANDAL AND A. K. BAJPAI Central Sericultureal Research and Training Institute Central Silk Board, Berhampore-742101, Murshidabad, West Bengal ABSTRACT Silk is the most prized natural fibres and known as “Queen of Textiles” for its gorgeous fall, grace and texture , produced by mulberry silkworm Bombyx mori L. It is a monophagous insect feeds solely on mulberry (Morus sp.) leaves which play most important role (38.2%) among the various factors that influence the production of quality cocoon crop.The garden of mulberry meant for young age silkworm rearing is known as “ Chawki garden”. Soft, succulent leaves rich in protein and carbohydrate are required for chawki worms. Keeping this in mind, an attempt was made to instigate the effect of planting geometry in the form of paired row plantation [(150 cm+90 cm) x 60 cm] and spaced plantation (90 cm x 90 cm) in Chawki mulberry garden against the present farmers practice of 60 cm x 60 cm plantation. Pooled data of five crops revealed that plant height, no of branches/plant, no of leaves/plant and leaf yield/plant were significantly superior in the chawki leaves of paired row plantation in comparison to others. Important biochemical parameters were also found superior in paired row plantation. While feeding the Chawki worms with mulberry leaves harvested from the above three types of planting geometry, it was found that cocoon yield/100 dfls, Shell %, Filament length and Reelability % were also significantly superior in paired row plantation. Key words: chawki garden, Mulberry, planting geometry, paired row and spaced plantation, chawki worms, quality cocoon crop The Mulberry garden specially meant for. young age silkworm rearing is known as “Chawki garden”. Chawki rearing is a vital aspect of sericulture industry aiming to raise robust, healthy and vigorously growing stock of worms with an ultimate aim to produce qualitatively and quantitatively superior cocoon crop. . Tazima (1978) reported that in sericulturally developed countries like Japan, China and Korea about 90% of the farmers receive Chawki reared worms. The concept of Chawki garden of mulberry is introduced recently in India for production of quality leaves for Chawki worms For Chawki rearing, the leaf should be soft, succulent and rich in protein and sugar contents whereas for late age, mature and less succulent leaves are ideal (Krishnaswami, 1978 a). But from a general mulberry garden, such specific quality of leaves are not produced which affect adversely on quality cocoon production. Thus, a separate mulberry garden for quality leaf production for young age silkworm rearing is imperative (Dandin et al., 2002). High yield associated with high quality, is always desirable both for mulberry leaf yield and cocoon production. Quality of mulberry leaves is one of the major factors influencing the healthy growth of silkworms and subsequently successful cocoon harvest. The quality of mulberry leaves also depends on number of factors such as genotype, package of practices, control of pest and diseases etc. (Patil 1998). It has been observed that silkworm is a highly sensitive insect and responds sharply to change in the feed quality. Parpiev (1968) reported the effects of high leaf water content (LWC) on the palatability and assimilability of nutrients . LWC also affects the growth and development of silkworms (Paul et al.,1992). Higher LWC is known to increase the amount of leaf ingestion and digestion capacity of silkworm through its olfactory and gustatory stimulant effect (Ito,1963).At the same time protein is also one of the important constituents of cell for monitoring the metabolic activities of silkworm body, silk & egg production ( Zuhua,1994). Among the leaf biochemical constituents , the total nitrogen, total soluble sugar and total soluble proteins are considered to be the important parameters favoring larval growth and cocoon yield ( Horie,1980). Further, higher level of leaf chlorophyll is indicative of photosynthetic efficiency of the plant system ( Patil,1998) Keeping this in mind, an attempt was made to instigate the effect of planting geometry in the form of paired row plantation [(150 + 90 cm) x 60 cm] and wider plantation (90 x 90 cm) in Chawki mulberry garden against the present farmers practice of 60 x 60 cm plantation with a goal of production of quality Chawki mulberry leaves and ultimately superior cocoon crop. MATERIALS AND METHODS The experiment was carried out under assured irrigated condition at Central Sericultural Research & Training Institute, Berhampore, Murshidabad, West Bengal during 2006 -2007. The high yielding mulberry variety, S1635 was selected for the experiment as it was found best for Chawki rearing . E mail : csrtiber@rediffmail.com Journal of Crop and Weed, 5(1):44-47 (2009)