EFFECT OF GROWTH REGULATOR - CHLORO MEPIQUAT CHLORIDE AND HIGH DENSITY PLANTING ON GROWTH AND YIELD OF Bt COTTON
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Date
2011
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ACHARYA N.G. RANGA AGRICULTURAL UNIVERSITY
Abstract
A field experiment entitled “Effect of growth regulator chloro mepiquat
chloride and high density planting on growth and yield of Bt cotton” was conducted
during kharif 2010 on sandy clay loam soil at College Farm, College of Agriculture,
Acharya N.G. Ranga Agricultural University, Rajendranagar, Hyderabad. The
experiment was laid out in Randomized Block Design, with factorial concept,
replicated three times. The treatments consisted three plant densities viz., 18,518
plants ha-1(90 cm x 60 cm), 24,691 plants ha-1 (90 cm x 45 cm) and 37,037 plants ha-
1 (90 cm x 30 cm) and four canopy management practices viz., control (no spray), detopping
at 50-60 DAS, single spray of growth regulator chloro mepiquat chloride @
0.2 ml l-1 at 50-60 DAS and two sprays of chloro mepiquat chloride @ 0.2 ml l-1 at
50-60 and at 80-90 DAS.
Crop growth measured at different stages as plant height and dry matter
production of Bt cotton was significantly higher when planted at a plant density of
37,037 plants ha-1 (90 cm x 30 cm) over that of lower densities of 24,691 plants ha-1
(90 cm x 45 cm) and 18,518 plants ha-1 (90 cm x 60 cm). The growth regulator
chloro mepiquat chloride, as such, had a profound influence on all the growth
parameters. The plant height, height to node ratio and dry matter accumulation was
significantly reduced with its application compared to control plot and de-topping
treatment.
At 110 DAS, as well as at final harvest the number of sympodial branches per
plant were significantly higher with 90 cm x 60 cm (20.36) followed by 90 cm x 45
cm (20.16) and 90 cm x 30 cm (19.81) spacing. The number of bolls per plant and
boll weight (g boll-1) were significantly higher with 90 cm x 60 cm (35.10 plant-1,
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5.58 g) followed by 90 cm x 45 cm (29.24 plant-1, 5.50 g) and 90 cm x 30 cm (20.76
plant-1, 5.39 g) spacing. The better yield components observed at wider spacings
could not compensate the gain due to higher number of plants per hectare at closer
spacing of 90 cm x 30 cm (37,037 plants ha-1) which has ultimately resulted in
greater seed cotton yield (1668 kg ha-1) over that of lower plant densities.
The yield parameters like sympodial branches per plant (20.76), number of
bolls per plant (35.89) and boll weight (5.62 g) were greater with spraying of chloro
mepiquat chloride twice followed by single spray (20.43 plant-1, 32.38 plant-1, 5.56
g) compared to control (19.61 plant-1, 22.33 plant-1, 5.38 g) and de-topping (19.64
plant-1, 22.89 plant-1, 5.40 g) treatment. Similarly the seed cotton yield was
significantly higher with two sprays of chloro mepiquat chloride (1635 kg ha-1)
compared to single spray (1556 kg ha-1), de-topping (1310 kg ha-1) and control (1282
kg ha-1) plot.
At higher plant populations (90 cm x 30 cm and 90 cm x 45 cm spacings)
nitrogen, phosphorus and potassium uptake by stalk was significantly higher
compared to lower density (90 cm x 60 cm). The chloro mepiquat chloride
treatments recorded higher uptake of nitrogen and lower uptake of phosphorus and
potassium compared to de-topping treatment and control plot at110 DAS and at crop
harvest.
The high density planting of Bt cotton coupled with application of chloro
mepiquat chloride @ 0.2 ml l-1 twice at 50-60 DAS and at 80-90 DAS recorded
higher seed cotton yield (1905 kg ha-1) and net returns (29,204 Rs ha-1) with a B:C
recorded of 2.05 than other treatment combinations.
Description
Keywords
planting, cotton, yields, biological development, inorganic acid salts, spacing, cellulose products, sowing, thinning, harvesting