Agricultural Research Management Information System

Home
Research Summary
Search
About Us
- ARMIS
- Brochure
Contact Us
Report
User Request
Data Input
Help
- Operation Manual
  - PDF
  - Video
- Program Area & Commodity
We have reached 37600 number of research entries at this moment.

- Logout

Research Detail

Home
Research
Detail

Effect of Defoliation on Growth and Yield in Soybean

M. R. Ali
Former MS student
Department of Crop Botany, Bangladesh Agricultural University, Mymensingh, Bangladesh

M. Monjurul Alam Mondal, PhD
Principal Scientific Officer
Crop Physiology Division, Bangladesh Institute of Nuclear Agriculture, BAU Campus, Mymensingh-2202, Bangladesh

Dr. M. A. Malek
Principal Scientific Officer
Plant Breeding Division, Bangladesh Institute of Nuclear Agriculture, BAU Campus, Mymensingh-2202, Bangladesh

Abstract/ Executive Summary:

Pot experiments were conducted at the pot yard of Bangladesh Institute of Nuclear Agriculture, Mymensingh, Bangladesh, during the period, January to April 2005 to investigate the effect of defoliations on dry mass production, yield and yield attributing characters in soybean. The treatment consists of alternate leaf removal at 4, 6, 8, 10, 12 or 14 weeks after sowing and no defoliation. Results showed that defoliation reduced the height of plant, number of side branches, total dry biomass plant^-1, weight of individual pod, number of pods/plant and seed yield. The defoliation 4 weeks after sowing had the greatest adverse effect on the number of side branches, while defoliation at 12 weeks after sowing had the greatest adverse effect on pod number, the size of individual grains and the shelling percentage. The degree of reduction in grain yield was greater than the reduction in pod number when defoliated at 12 weeks after sowing. This indicates that a large number of pods formed before defoliation was not filled.

Keywords: Defoliation, Seed yield, Soybean

Location: Pot yard of BINA, Mymensingh

Start Date: 00-01-2005

End Date: 00-04-2005

Program Area: Crop-Soil-Water Management

Commodity: Soybean

Objectives:

To find out the likely effects on seed yield due to defoliation of soybean by insects and also to determine the critical stage in the growth cycle when severe defoliation is likely to result in a considerable reduction in grain yield of soybean.

Methodology:

The pot experiments was conducted at the pot yard, Bangladesh Institute of Nuclear Agriculture, Mymensingh during January to April 2005. A completely randomized design with six replications was used in this study. A widely cultivated variety, Shohag was used for the investigation. The pots were filled with 12 kg sandy loam soil considered proper for soybean cultivation. The fertilizers were applied at the rate of 18.4, 40.0, 25.0 and 10.0 kg ha^-1 for nitrogen, phosphorus, potash and sulphur, respectively in form of urea, triple superphosphate, muriate of potash and gypsum. Two plants pot^-1 were kept two weeks after germination for growth and development, which denoted a replication. The treatment consists of alternate leaf removal at 4, 6, 8, 10, 12 or 14 weeks after sowing and no defoliation. During harvest, yield and yield components, dry matter production and its partitioning into plant parts were recorded. The total dry matter plant^-1 was estimated by summing dry matter of leaves, stem, and roots per plant. The collected data were analyzed statistically.

Source of Information: Research on Crops, 14 (3): 500-506, 2013

Article Link (Online Journal):

Funding Source:

1. Government

Budget:

Total Budget (Tk.) :

Achievement/Findings:

Leaf area, the most important source for dry matter (DM) and sink production since source (leaf) removal in the canopy decreased DM production. Defoliation not only decreased source size but also sink production resulting in lesser pods and seed yield. However, such reduction in TDM and seed yield plant^-1 was more pronounced when defoliation was done at early reproductive growth stages. Therefore, insect control measure should be taken at early reproductive growth stages. This study on the effect of defoliation on growth and grain yield in soybean highlights the need for careful timing of allocation of insecticides intended to control leaf-eating insects or application of fungicides intended to control leaf-destroying pathogens. The adverse effect of leaf removal during the early reproductive stage on grain yield in soybean plants tends to suggest that control of pests and diseases, which may reduce considerably the leaf area of the plants, should be carried out during the early rather than the late reproductive stage of soybean.

Knowledge Management: Journal