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

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proportion, by p. ˆ Any estimate of the proportion of infected seeds can vary from the true proportion due to sampling variation. The estimated sampling variation based on the formula p ˆ (1-p)/n ˆ at varying sample size (n) and proportion of infected seeds is computed and shown in Table 4.1. As sample size increases, sampling variation decreases. As the true proportion of infected seeds approaches 50%, sampling variation increases. When the true proportion of infected seeds is relatively low (i.e.,
solid pointed end. The tube and sleeve have open slots in their walls. When the slots are alined, seeds drop into the cavity of the tube. To close the slots, turn the tube. Tube length and diameter depend on the size of the container and kind of the seed to be sampled. The trier can be used horizontally for vertically. A vertical trier should be partitioned to assure even sampling through the layers. Insert the closed trier diagonally into the bag or container. Alter insertion, agitate it gently, and open and close it several times to ensure filling. Finally, close carefully before drawing out the sample. b) The Nobbe trier (Fig. 4.2a) is suitable for sampling seed in bags but not in bulk. It is constructed in varying dimensions depending on the kinds of seeds to be sampled. The Nobbe trier is a pointed tube, long enough to reach the center of the bag, with an oval hole near the pointed end, The instrument should be approximately 500 mm long, including the handle (about 100 mm long) and point (about 60 mm), leaving about 340 mm to penetrate the bag. This should reach the center of all types of bags. For cereals, the internal diameter of the tube should be about 14 mm. For clovers and similar seeds, 10 mm is sufficient. Insert the trier gently inlo the bag (Fig. 4.2b), pointing upward at an angle of about 30° to the horizontal, with the hole facing downward, until it reaches the center of the bag. Rotate the trier 180°, bringing the hole on top. Withdraw the trier with decreasing speed so the quantity of seed obtained from successive locations increases progressively from the center to the side of the bag. If, howerver, the trier is long enough to penetrate to the opposite side of the bag, withdraw it at a relatively constant speed. During withdrawal, the trier should be gently agitated to maintain an even flow of seed. The more polished the inner surface of the trier, the more freely the seed will flow. To sample the bottoms of standing bags, raise them off the floor and place them on top of other bags. The holes that the trier made in the bags may be closed by pushing the weave back together. c) Sampling by hand is difficult, and should not be used for chaffy seeds like rice. 3. Taking primary samples (Rule 2.6.4) Primary samples of approxirnately equal size shall be taken from each container sampled. When the lot is in containers (including bags), the containers to be sampled shall be selected at random throughout the lot and primary samples drawn from top, middle, or bottom portions of the container but not necessarily from more than one position in any container. When the seed is in bulk or in large containers, the primary samples shall be drawn from random positions or depths. 4. Obtaining the composite sample (Rule 2.6.5) If the primary samples appear uniform, they shall be combined to form the composite sample. 4.1 A sleeve-type trier (grain probe). 4.2 a. Stick triers (Nobbe trier). b. Inserting a stick trier in a sack of rice to draw seeds. 20 Rice seed health testing manual
Page 2 and 3: A Manual of Rice Seed Health Testin
Page 4 and 5: Contents Foreword v Preface vi Part
Page 6 and 7: Foreword Intensive collaboration ch
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: Example. In a two-stage random samp
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
Page 60 and 61: Table 10.2. continued Disease Fungi
Page 62 and 63: Table 10.2. continued Disease Growt
Page 64: additional precaution, the multipli
Page 67 and 68: terracoat (5-ethoxy-3- trichloromet
Page 70: Part 3 Pests and pathogens CHAPTER
Page 73 and 74: elevant tests for determining the i
Page 75 and 76: Table 12.1 continued Family and spe
Page 77 and 78:
Cryptolestes pusillus Schonherr The
Page 79 and 80:
Rice weeviI Scientific name: Sitoph
Page 82 and 83:
CHAPTER 14 Fungal pathogens J.K. Mi
Page 84 and 85:
THE DISEASE—BROWN SPOT Sir John W
Page 86 and 87:
Symptoms Glumes are discolored, and
Page 88 and 89:
y low relative humidity. Released a
Page 90 and 91:
THE DISEASE—STEM ROT Stem rot was
Page 92 and 93:
THE DISEASE—SHEATH BLIGHT Sheath
Page 94 and 95:
Sarocladium oryzae is seedborne. Th
Page 96:
Although not currently considered a
Page 99 and 100:
Pseudomonas fuscovaginae Pathogen:
Page 101 and 102:
See Chapter 7 and Figure 15.4a for
Page 103 and 104:
Infected seeds and contaminated wat
Page 105 and 106:
For further details, see the Common
Page 107 and 108:
nonfluorescent) and Erwinia herbico
Page 109 and 110:
Franklin M T, Siddiqi M R (1972) Ap
Page 111 and 112:
Tai F L, Siang W N (1948) 'I-chu-hs
Page 113 and 114:
106 Rice seed health testing manual
Page 115 and 116:
108 Rice seed health testing manual
Page 117 and 118:
After autoclaving the medium, add t
Page 119 and 120:
smoniloid = having swellings at reg
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