INTRODUCTION

Sericulture is an agro-based, labour intensive, foreign exchange earning commercial activity. Sericulture has been successful in eradicating rural poverty, resulting in social as well as economic development of rural peo- ple. It includes the technical aspects such as increasing productivity of land as well as labour, stabilization of cocoon production, improvement of silk yarn, fabric and generating profitable income for rural people. The mul-

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Received 10th April, 2015

Accepted after revision 15th June, 2015 BBRC Print ISSN: 0974-6455

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berry raw silk production in India during 2012-13 was 18,715 MTs (Anonymous, 2013).

Mulberry leaves, which provides food to silkworm, Bombyx mori L. is of great economic importance in seri- culture as it suffices nutritional requirements of carbo- hydrates, proteins, moisture, essential vitamins, miner- als, etc., for silk worms. The quantity of leaf produced and its quality has direct influence on silkworm health and the quantity of cocoons produced. Thus, the prof- itability of sericulture and quality of cocoons depends

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on nutritive quality of mulberry leaves fed to growing larvae. About 70 per cent of the silk proteins produced by the silkworm are directly derived from the mulberry leaves. Hence, the major step in increasing the produc- tivity of silk is to increase the leaf yield per unit area coupled with improved leaf quality.

In this context, it was thought necessary to investi- gate the suitable planting system, which can maximize the leaf yield and quality of mulberry.

MATERIAL AND METHODS

Investigations were carried out to know the impact of spacing in mulberry on Growth and yield of leaves in mulberry Morus alba L. The experiments were conducted in University of Agricultural Sciences, Bengaluru, Col- lege of Sericulture, Chintamani during the year 2013-

14.The details of the material used and methodology followed during the investigation are presented in this chapter.

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a Completely Randomized Block Design with five treat- ments and four replications each. Hundred worms were maintained in each replication. Two rearings were con- ducted during October (2013) and April (2014).

Similarly, mulberry growth parameters were also analyzed using RCBD with five treatments and four rep- lications (Sundar raj et al., 1972).

TREATMENT DETAILS

T1- Feeding of silkworm on mulberry leaves raised in 9×3 ft spacing.

T2- Feeding of silkworm on mulberry leaves raised in 6×3 ft spacing.

T3- Feeding of silkworm on mulberry leaves raised in [(6+3)×3 ft] spacing.

T4- Feeding of silkworm on mulberry leaves raised in 3×3 ft spacing.

T5- Feeding of silkworm on mulberry leaves raised in [(5+3)×2 ft] spacing.

EXPERIMENTAL SITE

The field experiment was conducted in the College of Sericulture Chintamani. Geographically it is located in the Eastern Dry Zone (Zone - 5) of Karnataka and the geographical co-ordinates of the place are 13° 24’ North latitude, 70° 04’ East longitude. It is situated at an alti- tude of 857 m above mean sea level.

SOIL CHARACTERISTICS

The soil of the experimental site was red sandy loam, with pH range of 5.1 to 6.4 having good drainage. The soil is found to have rocky sub-strata in the deeper lay- ers. The fertility status is poor to medium. Crust forma- tion on drying is found to be major problem of this soil type.

WEATHER DURING CROP GROWTH PERIOD

The data on climatic parameters viz., total rainfall(mm), number of rainy days, temperature (oC), relative humid- ity(%), evaporation(mm), sunshine(hrs) according to the standard weeks during the crop growth period are col- lected from meterological observatory located at ARS, Chintamani and are presented in Appendix-I. Daily meteorological data during rearing period, are presented in Appendix-II.

DESIGN AND DETAILS OF REARING

Mass rearing of silkworms was done till third moult, using S-36 leaves the late age worms were reared on V-1 variety with different spacings, experiment was laid in

GROWTH AND YIELD PARAMETERS OF MULBERRY

Mulberry was raised under the spacing of 9×3 ft, 6×3 ft, (6+3)×3 ft, 3×3 ft, (5+3)×2 ft following the package of practices and below observations were recorded.

1. Plant height (cm)

Plant height was recorded from the base of the plant to the tip of the apical bud. The mean of five plants were considered to calculate the plant height.

2. Number of branches per plant

The number of branches in five plants per treatment was counted and mean number of branches was calculated.

3. Number of leaves per plant

Total numbers of fully opened green leaves in five plants per treatment were counted and their average was cal- culated per plant.

4. Single leaf area (dm2)

The area of third fully opened leaf from top was deter- mined by multiplying length × breadth with a constant factor (0.6898).

5. Fresh weight of single leaf (g)

Fresh weight of single leaf was recorded by weighing single leaf immediately after picking using electronic sensitive balance

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6. Leaf yield (g/plant)

Leaf yield per plant was recorded on fresh weight basis.

MOISTURE RETENTION CAPACITY OF MULBERRY LEAF (%)

Moisture retention capacity (MRC) in harvested leaves was recorded from bottom leaves. Leaves were allowed to dessicate at room temperature for 3, 6, 9, 12 hours and were then dried in an oven at 800 C. Moisture retention capacity was calculated using the following formula:

Where,

FWi = Fresh weight at particular time period (3, 6, 9 and 12h after harvest).

DW = Oven dry weight.

FWo = Fresh weight immediately after harvest.

RESULTS AND DISCUSSION

The major goal of the study was to evaluate the perform- ance of mulberry leaf characters and silkworm growth and cocoon parameters, from this context the existing mulberry garden with different spacing were used for

the study. The results of the present investigation “The impact of spacing on growth, yield and biochemical constituents of leaves in mulberry Morus alba. L.” are discussed below.

GROWTH AND DEVELOPMENT OF MULBERRY AT DIFFERENT SPACING

In the present investigation the plant height was found significantly superior in 9×3 ft spacing (183.44 cm), fol- lowed by (6+3)X3 ft spacing (173.63 cm) and least was observed in 3 ×3 ft spacing (93.59 cm). This might be due to spacing effect, where, wider spacing has much scope for vigorous growth with no competition for nutrients and space. Similar results were also noticed by Ghosh et al. (2009) who reported that contributing characters and leaf yield were significantly superior in paired row plantation (150+90)X60 cm.

Mean number of branches and leaves per plant were also recorded highest in 9×3 ft spacing 13.00 branches and 265.00 leaves followed by (6+3)×3ft spacing 11.25 branches and 254.50 leaves, when compared to closer spacing of 3×3 ft 7.00 branches 145.75 leaves. This might be due to increased plant height and good crop stand of the plant in wider spacing with no competi- tion for spreading of the branches. Increased number of leaves per plant is mainly because of increased plant height and number of branches. Leaf area was also found higher in 9×3 ft spacing (274.10 dm2) followed by

(6+3)×3ft spacing (211.03 dm2) and lowest was recorded in 3× 3 ft spacing(132.80 dm2) this might be due to the sufficient sunlight, aeration and also abundant sup- ply of the nutrients and moisture. This is in conformity with observations of Sawalgi and Patil. (2003). Murthy et al., (2013) also observed that mulberry variety Vishwa grown with a spacing of 4×4 ft showed highest number of shoots per plant, longer shoot length and shorter internodal distance.

Fresh weight of single leaf and leaf yield was recorded to be highest in 9×3 ft spacing (4.66 g and 1234.90 g, respectively) followed by (6+3)×3ft spacing (3.50 g and

890.75g respectively) when compared to closer spacing of 3×3 ft (2.10 g and 306.00 g respectively). This is may be due to abundant space for root spread, high uptake of the nutrients and moisture and also due to increase in leaf yielding contributers like plant height, number of

branches and leaves. This is in conformity with Eltayb et al., (2013) who found that M.alba and M. mesozygia recording highest weight of leaves and yield per unit

area in 1.00×1.00 m and 1.50×1.00 m. Similar results were also observed by Ramakanth et al., (2001).

Moisture retention capacity was found to be higher in wider spacing of (6+3)×3 ft at 3,6,9,12 h, (88.12 %, 86.02 %, 85.16 % and 84.16 % respectively) after harvest and lowest was recorded in closer spacing of 3×3 ft at 3, 6, 9, 12 h (79.45, 76.30, 75.10 and 74.33, respectively). This might be due to leaves grown under wider spacing were broad, thick and more succulent and these findings are in conformity with Murthy et al., (2013) where he found moisture retention capacity was good in 4 ×4 ft spacing.

REFERENCES

Anonymous (2013). Highlights of activities. Annu. Rep., Cen- tral Silk Board, Bangalore, pp.1.

Eltayb M. T., Warrag E. E. and Ahamed A. E. (2013). Effect of spacing on performance of Morus species. Journal of Forest Products and Industries 2(3): 13-23.

Ghosh A., Dutta T., Saha A. K., Shivnathkar N. B., Mandal K. and Bajpai A. K. (2009). Effect of planting geometry on leaf yield and quality of mulberry chawki garden. J. Crop and Weed 5(1): 44-47.

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Miyashita Y. (1986). A Report on Mulberry Cultivation and Training Methods Suitable to Bivoltine Rearing in Karnataka. Central Silk Board, Bangalore, India, pp. 1-7.

Murthy Y. V. N., Ramesh H. L. and Munirajappa (2013). Evalu- ation of mulberry (Morus) variety for leaf yielding parameters and phytochemical analysis under different spacing systems. Indian Journal of Applied Research 3(8): 31-33.

Ramakant B. D., Singh A., Sarkar A. and Hasegawa K. (2001). Effect of different plant geometry and levels of fertilizer on

yield of semi-mechanized mulberry garden under irrigated condition for corporate sector. Proc. Natl. Sem. Mulb.Ser. Res. India., pp.288-294.

Sawalgi S. and Patil G. M. (2003). Intercropping of chilli varie- ties in paired row planted V-1 mulberry and its impact on silk- worm (Bombyx mori). Karnataka J. Agric. Sci. 16(4): 609-611.

Sundar Raj N., Nagaraju S., Venkataramu M. N. and Jagannath M. K. (1972). Design and Analysis of Field Experiment, Unvi. Agri. Sci., Bangalore, p.143.