A manual of rice seed health testing - IRRI books - International Rice ...

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Foreword Intensive collaboration characterizes the international exchange of rice germplasm. Efforts to increase rice yields demand that more germplasm be exchanged, more often. In 1992, IRRI dispatched 94,836 seed lots to rice scientists world wide and received 6,270 seed lots from outside the Philippines. This exchange of rice germplasm can be expected to increase exponentially as national breeding programs intensify their work and rice scientists strive to increase rice yields through breeding resistance to pests and tolerance for abiotic stresses into new varieties, to feed the growing number of rice consumers of the future. But any exchange of crop materials involves the inherent risk of also exchanging pests and diseases. Certification of seed health involves three basic issues: Identifying the organisms that have quarantine importance. Determining the optimum sample size of a seed lot to test for those organisms. Using standard procedures to carry out the tests. IRRI established its Seed Health Unit in 1983, in cooperation with the Plant Quarantine Service of the Bureau of Plant Industry of the Philippines. Staff members of the unit work to ensure that incoming seed lots consigned to IRRI meet or exceed Philippine quarantine requirements and that seed lots IRRI sends out meet or exceed the quarantine requirements of the countries to which they are consigned. Many methods have been developed, tested, and modified to meet the need for safe and rapid exchange of rice germplasm and breeding materials. The Seed Health Unit also offers a short course on seed health maintenance and testing procedures to help improve the speed and safety of rice seed exchange worldwide. First offered in 1990, the course provides comprehensive, hands-on experience in all aspects of rice seed health testing. This manual is based on the content of the short course. Tests for seedborne fungi are those used by IRRI's Seed Health Unit. Tests for bacteria are based on procedures used by IRRI's Plant Pathology Division. Diagnostic tests for viruses are not included because no tropical viruses are known to be borne by rice seeds. Standard procedures accepted by the International Seed Testing Association are described, in particular those on sampling (ISTA 1985). Dr. J.K. Misra, visiting scientist at IRRI 1988-90, compiled the first draft. Staff of the Seed Health Unit; the Agronomy, Plant Physiology and Agroecology; Entomology; and Plant Pathology Divisions; and of the Genetic Resources Center and Biometrics Unit provided additional detail. Dr. T.W. Mew integrated the many contributions. The manual was edited by Jill Gale de Villa, assisted by Teresita Rola, with graphic design by Ramiro Cabrera, Communication and Publications Services. Klaus Lampe Director General
Preface In the last few decades, the international exchange of plant germplasm (seed) has increased tremendously. Global cooperation to boost food production and combat hunger has revolutionized agricultural production and, at the same time, has increased the risk of introducing exotic pests and pathogens. Consequently, the quarantine officials’ job has become increasingly complex and challenging. Quarantine personnel deal with a wide range of outgoing or incoming plant and other materials, their pathogens, and other undesired objects accompanying them. It has become difficult, if not impossible, for the limited number of people working at quarantine stations to know intimately the bizarre group of organisms associated with the various crops that frequently pass through them. Thus, specialists dealing with specific crops and pathogens should publish all relevant information. The publications should be geared to help the users, be they scientists or tradesmen, allow safer, uninterrupted movement of germplasm. Yet, this type of publication is unavailable for many crops which are exported. Rice is exchanged widely for both scientific and commercial purposes. Shortly after its founding, the International Rice Research Institute (IRRI) started exchanging seed for scientific purposes. In recent years, these exchanges have occurred with increasing frequency. Between 1985 and 1990, IRRI dealt with 936,547 seed lots (IRRI’s Seed Health Unit data). Many other organizations are engaged in seed exchange for scientific purposes. There is enormous movement of seed for commercial purposes. This manual compiles important information relating to common seedborne rice diseases and rice seed contaminants, details of the causal organisms, and methods of detecting their presence. The manual has three major divisions. Part I discusses the importance of seeds, their health, and the risks involved in seed exchanges; reviews the historical development of quarantine systems; and describes rice plant morphology and ecosystems. Part II describes laboratory equipment needed for assessing rice seed health; samples and sampling methods; dry seed inspection; detection, isolation, and identification methods for fungi, bacteria, and nematodes; viruses and mycoplasmalike organisms (briefly mentioned); and methods for field inspection and seed treatment. Only methods pertinent to assessing seed health for quarantine are included. Part III describes the pathogens and the diseases they cause. Appendix 1 contains sample recording sheets. Lists of media, stains, and reagents are given in Appendix 2 and some recipes for preparing them. Appendix 3 is a glossary of terms used in this manual. References cited in the text are listed before the appendices. We hope this manual, and our approach to seed health, will help the readers assess rice seed health properly. However, no work can claim to be complete. There is always room for correction and/or amplification. We intend to update and improve this manual in the future, and thus ask that you send us suggestions and comments that will make future editions more complete and more useful.
Page 2 and 3: A Manual of Rice Seed Health Testin
Page 4 and 5: Contents Foreword v Preface vi Part
Page 8: Part 1 Introduction CHAPTER 1 Rice
Page 11 and 12: tional levels (Kahn 1988). Quaranti
Page 13 and 14: Morphology of the mature plant Matu
Page 15 and 16: two-celled, besifixed, deeply sagit
Page 18 and 19: Part 2 Procedures for seed health e
Page 20 and 21: CHAPTER 3 Equipment J.K. Misra, T.W
Page 22: 3.2 Dry seed inspection using a mag
Page 25 and 26: Example. In a two-stage random samp
Page 27 and 28: solid pointed end. The tube and sle
Page 30: CHAPTER 5 Dry seed inspection J.K.
Page 33 and 34: Detection Blotter and agar plate me
Page 35 and 36: Results: Examine plates for charac-
Page 37 and 38: Extraction and isolation It is esse
Page 39 and 40: GRINDING METHOD (FOR SMALL-SCALE SE
Page 41 and 42: flagellum. Cells occur singly, in p
Page 43 and 44: 7.6 Oxidase test reaction. L = colo
Page 45 and 46: 7.9 Production of 2-ketogluconate.
Page 47 and 48: 1. Grow pathogen-free plants under
Page 49 and 50: 7.12 a. P. glumae type A colony on
Page 51 and 52: A1. Macerate 100 seeds in 10 ml of
Page 53 and 54: Results: 7.Streak the bacteria onto
Page 55 and 56: Sieve method (Fig. 8.1) Procedure:
Page 58 and 59:
CHAPTER 10 Field inspection J.K. Mi
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Table 10.2. continued Disease Fungi
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Table 10.2. continued Disease Growt
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additional precaution, the multipli
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terracoat (5-ethoxy-3- trichloromet
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Part 3 Pests and pathogens CHAPTER
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elevant tests for determining the i
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Table 12.1 continued Family and spe
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Cryptolestes pusillus Schonherr The
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Rice weeviI Scientific name: Sitoph
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CHAPTER 14 Fungal pathogens J.K. Mi
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THE DISEASE—BROWN SPOT Sir John W
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Symptoms Glumes are discolored, and
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y low relative humidity. Released a
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THE DISEASE—STEM ROT Stem rot was
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THE DISEASE—SHEATH BLIGHT Sheath
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Sarocladium oryzae is seedborne. Th
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Although not currently considered a
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Pseudomonas fuscovaginae Pathogen:
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See Chapter 7 and Figure 15.4a for
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Infected seeds and contaminated wat
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For further details, see the Common
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nonfluorescent) and Erwinia herbico
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Franklin M T, Siddiqi M R (1972) Ap
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Tai F L, Siang W N (1948) 'I-chu-hs
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106 Rice seed health testing manual
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108 Rice seed health testing manual
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After autoclaving the medium, add t
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smoniloid = having swellings at reg
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