Dey et al.

nutritional disorders in lowland rice producing areas

720 mm. The deficiency in rainfall was 27.4% in

of the world. Hybrid rice production technology

2011. The soil of the experimental plot was sandy

aims to increase the yield potential of rice beyond

loam in texture (62.5% sand, 26.0% silt and 10.5%

the level of inbred high yielding varieties (HYV)

clay), neutral in reaction (pH 6.1) medium in organic

by exploiting the phenomenon of hybrid vigour.

carbon (0.49%) and available N (136.0 kg ha -1 ), low

Besides other agronomical inputs optimization of

in available P (11.5 kg ha -1 ) and available K (160.5 kg

nitrogen and spraying of suitable phytohormone

ha -1 ) status. The experiment was laid out in factorial

are extremely important and maximum yields are

Randomized Block Design with three replications

possible when nitrogen uptake is sufficient to sustain

in 4 m x 2.5 m plots with five nitrogen levels (N ₀ = 0

biomass accumulation, sink formulation throughout

kg N/ha (control), N ₆₀ = 60 kg N/ha, N ₁₂₀ = 120 kg N/

the crop growth and development period. Proper

ha, N ₁₈₀ = 180 kg N/ha, N ₂₄₀ = 240 kg N/ha) and three

nitrogen fertilization is an important management

spraying of homo-brassinolide (at Active tillering

practice which can increase the yield of hybrid rice.

(AT), Active tillering + Panicle initiation (PI) and

Proper and optimum N applied gave maximum

Active tillering + Panicle initiation + Flowering). The

filled grain percentage, 1000-grain weight, grain and

hybrid rice GAP 4011was transplanted on July July

straw yield of hybrid rice (Peng et al., 1996). Maske

29, 2011 taking single seedling per hill at 25 x 25cm.

et al., (1997) accounted that increasing nitrogen

All plots received full dose of P and K and 1/4 th N

levels up to 120 kg N/ha significantly increased plant

fertilizer at basal and remaining N fertilizer in three

height, leaf area, yield component and grain yield of

equal splits - at mid-tillering, panicle initiation and

rice. Brassinosteroids are a class of plant polyhydro-

flowering as per treatments. The crop irrigated

xysteroids that are ubiquitously distributed in the

as and when required. The weeds were removed

plant xysteroids that are ubiquitously distributed

manually at 30 and 45 days after transplanting

in the plant xysteroids that are ubiquitously

(DAT). Harvesting was done on November 11, 2011.

distributed in the plant kingdom. These compounds,

The observation on plant height was recorded from

when applied to plants, improve their quality and

10 hills randomly selected in each plot at different

yield Brassinolide (BL), considered to be the most

stages and their average was worked out. Tiller

important homo-brassinolide (HBR) playing a

number from the same hills was also recorded at 60

pivotal roles in the hormonal regulation of rice plant

DAT. Samples for biomass has been collected from

growth and development, and its ability to induce

5 hills from ear-marked area and dried in an oven

disease resistance in rice plants was analyzed by

at 65-70°C till constant weights were obtained. The

Nakashita et al., (2003).

dry weight of were noted and converted into g m -2 .

The dry weight of leaves was used for determining

Materials and Methods

leaf area index (LAI) as suggested by Watson (1952).

A field experiment was conducted during the

DMA at different stages was used for determining

kharif season of 2011 to study the effect of nitrogen

crop growth rate (CGR). Observation on yield

levels and time of homo-brassinolide spraying on

parameters like number of panicles m -2 , number of

growth and productivity of hybrid rice at the farm

spikelets and filled grains panicle -1 , test weight along

of the Institute of Agriculture (Palli Siksha Bhavana),

with grain yield, straw yield and harvest index were

Visva-Bharati, Sriniketan, West Bengal. The place

recorded at maturity. The data were statistically

is situated at 23°39 N latitude, 87°42’ E longitude

analyzed applying the techniques of analysis of

and an elevation of 58.9 m above mean sea level.

variance and the significance of different sources of

Normally the area received about 1000 mm rainfall

variations were tested by error mean square of Fisher

during the kharif season (July to October). But there

Snedecor’s ‘F’ test at probability level 0.05 (Cochran

was low rainfall during the crop season of 2011in

and Cox, 1977).

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