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

Seed Biology Relation with Seedling Emergence: Implications in Crop Production

M M Rahman
Department of Agronomy, Bangladesh Agricultural University, Mymensingh-2202, Bangladesh

Abstract/ Executive Summary:

Uniform and rapid seedling establishment are very important aspects in successful crop production. The seedling establishment largely depends on the germination response of the seed to the environment and their inherent physical and physiological conditions. Non-dormant seeds under favourable environmental conditions pass through a complex process of germination. Germination starts with imbibition and is completed by visible radicle protrusion through the seed covering layers followed by seedling establishment. Seeds fail to germinate due to presence of dormancy. Poor and non-uniform germination occur with low vigour seeds. Seed dormancy is generally an undesirable characteristic in many agricultural crops but some degree of dormancy is advantageous, at least during seed development, to prevent pre-harvest sprouting in many crops such as wheat and rice. Seed dormancy is an innate seed property caused either by presence of chemicals or physical barrier by seed coats. The dormancy caused by chemicals is controlled by different signal transduction pathways mediated by environmental and hormonal signals that regulate gene expression by seeds. Little is known about the interconnected key molecular processes controlling dormancy and germination in response to hormonal and environmental cues. The dormancy is a dynamic process and is influenced by the seed biology and environment duration seed development, maturation and storage. The germination and vigour of seed are also influenced by the environment during seed development, maturation and storage. The status of germination and vigour is determined during seed development and maturation. This quality can not be improved by any means during processing and storage but could be maintained through judicious handling and storage techniques. However, germination and vigour improvement in seed could be made by different physical or chemical treatments during early seed germination process. Dormancy and germination of seed could also be manipulated by different physical or chemical mechanisms towards rapid and uniform seedling establishment as well as declining weed density. Thus a deep insight into seed dormancy, germination and vigor mechanisms could help developing techniques toward improving seedling establishment of different crops under variable field environments.

Keywords: Seed biology, Germination, Dormancy, Viability, Seedling establishment and priming

Location: Department of Agronomy, Bangladesh Agricultural University, Mymensingh

Start Date: 00-00-2013

End Date: 00-00-2013

Program Area: Seed Technology

Non-commodity: Performance

Objectives:

The present paper describes different aspects of dormancy and germination as well as mechanism of loss in seed viability.

Methodology:

Determination of seed viability: Seed germination is lost because of seed deterioration. Therefore, seed should be tested for its germination performance before sowing in the field. Seed viability is synonymous to germination capacity of seed lot which refers to the potentiality of seeds to germinate and produce normal seedling under favourable environment. Seed viability is mostly assessed by the standard germination test. The germination test requires a relatively longer period of time. Therefore, other methods are also employed for estimating seed viability. These methods measure vital physiological and biochemical activities of seeds essential for their survival and germination. These methods include germination test, membrane permeability test, seed viability test through an automatic seed analyzer, phospholipids determination, lipid peroxidation measurement, estimation of alpha-tocopherol and measurement of respiration. Lipid peroxidation measurement is based on the estimation of malondialdehyde content of seeds. This parameter is often considered as a good indicator of seed quality. Peroxidation of unsaturated fatty acids is regarded as a prime cause of seed deterioration. Seeds contain some antioxidants which interrupt the chain of reactions involved in fatty acid peroxidation, they achieve this by associating with the free radicles of the intermediate molecules. The major antioxidants present in seed membrane and storage lipids are tocopherols, particularly alpha-tocopherol or vitamin E. Therefore, alpha-tocopherol concentration in seeds provides a good indicator of seed ageing. Determination of seed vigour: The actual germination performance of a seed lot depends on the vigour of the seed. Seeds are subjected to diverse environment under field condition and therefore, the performance of seed is the outcome of the interaction between seed quality attribute and the field environment. The sum total of the quality attributes which determines the potential level of activity and performance of the seed or seed lot during germination and seedling emergence. Seed vigour is a quantitative character controlled by a number of factors affecting the performance of seed and seedling. Seed germination tests are done under favourable conditions in the laboratory, which is seldom relate to field condition. Since, germination test values often overestimates actual field emergence and therefore, vigour test is required to achieve information on the field performance of seed lot. Vigour tests provide more sensitive index of seed quality than the germination test and therefore, seed vigour tests are required to get prior information about the seed lot. A number of vigour tests are used which includes, (i) Conductivity test, (ii) Accelerated ageing test, (iii) Cold test for maize, soybean, sorghum etc., (iv) Controlled deterioration test, (v) Complex stressing vigour test (CSVT), (vi) Hiltner test, (vii) Seedling growth tests, (viii) Vigour index, and (ix) Tetrazolium test.

Source of Information: SSSB (Seed Science Society of Bangladesh). 2013. Proceedings of the Third International Conference on Quality seed for food security under changing climate, 8-10 February, 2012, Bangladesh Agricultural University, Mymensingh, Bangladesh.

Article Link (Online Journal):

Funding Source:

Budget:

Total Budget (Tk.) :

Achievement/Findings:

Seedling establishment depends on the viability and vigour of seed as well as the seed bed environment. Sowing at wrong environment causes severe decline in seedling emergence and subsequent establishment. The viability and vigour of the stored seed could be maintained by choosing right processing and storage technology. Moreover, high quality seed production depends on best agronomic management practices that ensure proper growth and development of seed. There is a need of measuring the viability and vigour of seed before selling or sowing. Moreover, dormancy breaking is the must before sowing where applicable. However, the rate and speed of seedling emergence could be improved by different techniques such as seed priming and seed treatment. Thus, seed quality maintenance during production, processing and storage as well as enhancing of seed priming could ensure optimum plant establishment to achieve high yield of crops. Therefore, a deep understanding on seed biology in relation to germination, vigor and dormancy is the prerequisite for developing proper techniques to successful seedling establishment.

Knowledge Management: Report/Proceedings