Programme
Session 1: Technologies for improved seed supply
Aspects of seed production related to seed quality during conventional and organic production; genetic conservation for breeding and diversity; participatory plant breeding; seed supply and development of seed testing in developing countries; seed health issues during production; physical and chemical seed treatments; seed moisture testing
Chair and lead speaker: PK Agrawal, Prasha Agri Consultants Pvt. Ltd., H-126, Ashok Vihar, New Delhi-110052, India.
Presentation title: Seed led technology for better crop yield
The millennium challenge of producing more food from less land envisages high technological intervention. Seed is the delivery system through which most of genetic and biotechnological advancements get transferred for crop production. Combination of better genetic potential with biotech-enabled traits like insect protection and weed management, better agronomic techniques and tools has improved crop yield. In India Bt cotton can be cited as an example for this success. Five cotton events encompass 80% of the total cotton cultivated area in India. Improved seed supply coupled with better agronomy facilitated a phenomenal increase in cotton production and India has become the 2nd largest cotton producer in the world. Technology has moved further. Seeds are now engineered to withstand a range of biotic stresses, enhance water and nitrogen use efficiency and to improve nutritive content. Biopharming and bioengineered ‘albedo’ plants are other emerging technologies whereby the scope of seed is widening beyond that of a mere agricultural commodity. [The co-author of this paper is Sherry R Jacob, ICAR Directorate of Seed Research, Kushmaur, Mau 275101, (UP), India].
Session 2: Aspects of purity: Genetic, technical and physical
Varietal identification; seed lot heterogeneity and sampling; automated and computer-based methods for seed identification and assessment; seed processing; GM testing, the co-existence of GM and conventional seed production; contamination with fungal fruiting bodies, weeds and parasitic plants
Chair and lead speaker: E Noli, Laboratory for Seed Research and Testing, Department of Agroenvironmental Sciences and Technologies, University of Bologna, Bologna, Italy
Presentation title: New tools for measuring genetic quality in seed
Plant breeding is widely recognized as the major single contributor to the dramatic increases in agricultural yields observed over the last century. The seed is the delivery system for the scientific advances and technological innovations that have been achieved through plant breeding. In this context, genetic quality, both in terms of identity and purity, is an important component of the overall seed value, and its maintenance is the objective of certification schemes. Identity preservation extends further down in the production chain to separate specialized products from generic commodities.
Biochemical markers were the first efficient tool for variety identity and purity testing, and they are currently applied both in variety registration and protection as well as in seed quality control. However, in the last two decades molecular marker technology has become widely utilized in all stages from basic research to quality control of agricultural products, through the intermediate steps of variety development and seed production. In fact DNA-based technologies are highly efficient for genetic characterization and allow both the tagging of specific traits and the detection and quantification of minute amounts of contaminants.
Session 3: Basic approaches to physiological processes in seeds (ISSS collaborative session)
Seed development and maturation; desiccation tolerance and its acquisition; water activity in seeds; regulation, induction and breaking of dormancy; genomics; genetic regulation and initiation of germination; stress tolerance; physiology of priming
Chair and lead speaker: G Leubner, Molecular Plant Sciences, Albert Ludwigs University, Freiburg, Germany.
Presentation title: Comparative seed biology will lead the way: Evolutionary conservation and biodiversity of physiological mechanisms that control germination.
Two opposing forces provide the basic physiological mechanism for the control of seed germination timing and synchrony: The growth potential increase of the embryo leading to cell-wall extension growth, and the restraint weakening of the various covering layers (envelopes). The latter include natural envelopes like endosperm, testa (seed coat), pericarp (fruit coat), as well as artificial envelopes applied by seed technologists. Research with seed model systems/species has started to provide an understanding of the molecular mechanisms underlying embryo growth, restraint weakening, dormancy, and the seed responses to environmental cues and abiotic stresses. Through adaptation, germination is timed to avoid unfavourable weather for subsequent plant establishment and reproductive growth. This adaptation seems to have taken place on a theme rather than via fundamentally different paths and similarities underlying the extensive diversity in the seed responses to the environment become evident. Interdisciplinary research approaches have combined molecular genetics, physiology, biochemistry, ecology, biomechanics, engineering and technology with post-genomic, bioinformatic and modelling techniques. These are on the way to providing an integrated, systems biology understanding of seed dormancy, after-ripening and germination. Comparative seed biology, with model, horticultural and crop species representing important phylogenetic clades and seed types, will lead the way to the identification of evolutionary conserved and species-specific mechanisms that control germination.
Session 4: Approaches to the evaluation and improvement of germination
Germination testing methods; dormancy in seed testing; viability testing; influence of storage and storage conditions on germination; seed collection and handling effects on germination and longevity; effects of insect pests and seed-borne pathogens.
Chair and lead speaker: J Léchappé, Geves-Station Nationale d'Essais de Semences, rue Georges Morel, Beaucouzé, 49070. France.
Presentation title: Seed germination tests: ubiquitous and up-to-date tests over the years? Influence of external factors as quality assurance and progress in research on the stability and the evolution of the tests.
Since the creation of the first seed testing laboratories at the end of the 19th century, germination tests have remained the reference tests for the seed trade, the seed industry in their aim to produce seeds of high quality, and for national and international regulations. Two aspects will be developed and discussed:
- The classical and standard germination tests, in the framework of quality assurance facilitate the equivalence of evaluation of the seed germination quality over the world regions, whatever the technological facilities of the laboratories may be.
- The input of research to the evolution of the classical tests (germination, tetrazolium, viability,...). Nowadays, more and more tests are available for tropical and subtropical species. Many applied research programmes aim to improve the performance of the tests, for example by shortening the duration, breaking the dormancy (GA3, KNO3). New tests are being added to the existing ones. Some are in the process of being adopted as routine tests (SBP-elisa, image analysis), whilst others are more prospective (e.g. molecular markers).
The interactions between the seeds presented for testing and accompanying additional elements, such as seed microflora (saprophytes or pathogens) and seed treatments, including chemicals with the possibility of phytotoxicity, and their influence on the way that test methods evolve, will also be discussed.
Session 5: Assessment an improvement of seed performance in practice
Causes of vigour differences (production, processing, physiological); vigour testing; impact of seed vigour on crop and transplant establishment; priming and other invigoration treatments; vision systems for seedling selection
Chair and lead speaker: S Matthews, School of Biological Sciences, University of Aberdeen, Aberdeen, United Kingdom.
Presentation title: Seed vigour: from one hypothesis to many predictions and uses.
Almost all vigour tests that are in use or proposed can be explained in terms of seed ageing and its consequences. Experimental evidence will be presented to support this hypothesis in a range of crops, including major field crops (e.g. maize and soyabean) and vegetables (e.g. legumes, brassics, cucurbits, pepper). The consequences of ageing, including electrolyte leakage into seed soak water and slower physiological germination, form the basis of many vigour tests. These tests differentiate the field and greenhouse emergence as well as the storage potential of seed lots that have similar and acceptable high levels of standard germination. The ageing hypothesis can be extended by interpreting differences in rate of germination as differences in the mean lag period between imbibition and radicle protrusion, during which the damaging effects of ageing undergo metabolic repair. This proposition will be used to explain stress tests (e.g. cold test for maize) and seedling growth tests (e.g. cool germination test for cotton) of seed vigour and some of the effects of seed priming. The implications for the rational search for rapid biochemical / molecular tests of seed vigour and for the selection of vigorous genotypes will be highlighted. This will provide a science-based theme for the oral and poster papers that follow in Session 5.
29th ISTA Seed Symposium - Scientific Programme Advisory Committee
- Alison A Powell (GB) Seed Symposium Convenor
- Theresa Aveling (SA)
- Valerie Cockerell (GB)
- Michael Kruse (DE)
- Joel Léchappé (FR)
- Julio Marcos Filho (BR)
- Augusto Martinelli (AR)
- Lea Mazor (IL)
- Enrico Noli (IT)
- Anne Bulow Olsen (DK)
- Robin Probert (GB)
- Zdenka Prochazkova (CZ)
- Brent Turnipseed (USA)
- Joost Van der Burg (NL)
