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In CES, 28 entries had low tungro incidence (0–23%). while in MES all entrieshad high tungro incidence (47-100%).In both locations, TI-11-8 showed low virus titers of combined RTBV and RTSV(0%), RTBV (8% in CES, 0% in MES), and RTSV (0% in CES, 13% in MES), indicatinga high level of resistance to tungro. In CES, IR74, PSB Rcl8, and PSB Rc34showed low infections with combined RTBV and RTSV (0–4%), with RTBV (0-4%), and with RTSV (0–25%). In MES, LS519, LS551, TK298, and TK300 had lowcombined RTBV-RTSV (8-25%), RTBV (4–25%). and RTSV (4–13%) infection.In 1996, the observation nursery in CES handled 399 entries, most of which wereF4 lines. Sixty-seven lines showed a high level of resistance to tungro. In MES, onlyone entry, IR69705-1-1-3-2-1, exhibited high resistance against tungro out of morethan 900 entries evaluated, the bulk of which were F 4 and F 3 lines.Generating RTD-resistant advanced linesThis task involves the following procedures: (1) advancing early generations of crossesbetween tungro-resistant genotypes and selected rice cultivars, (2) screening for RTDresistance in early and advanced generations, and (3) purifying and increasing seed ofselected lines that are resistant to RTD. Figure 1 shows the scheme for generationadvance and resistance screening.Hybridization work began in 1994, producing 14 crosses. In the succeeding years,many materials were handled in both the dry and wet seasons. In 1995, 70 crosses,256 F 1 plants from 42 crosses, and 17 F 2 populations were advanced. In 1996, 116crosses, 270 F 1 plants from 42 crosses, 16 F 2 populations. 1.047 F 3 lines from 24crosses, and 387 F 4 lines from 4 crosses were advanced. In 1997, 14 crosses, 18 F 2populations, 334 F 3 lines from 8 crosses, 464 F 4 lines from 16 crosses, 262 F 5 linesfrom 14 crosses, and 46 F 6 lines from 4 crosses were advanced. In 1998, 6 F 3 crosses,64 F 4 lines from 8 crosses, 226 F 5 lines from 8 crosses, 276 F 6 lines from 16 crosses,198 F 7 lines from 14 crosses, and 24 F 8 lines from 4 crosses were advanced.As of the 1998 WS, several F 8 lines from four crosses have been considered asthe best tungro-resistant selections. These include four lines from PSB Rc4 × TI-11-8, three lines from BPI Ri10 × TI-11-8, and one line from IR64 × TI-11-8. Table 2shows the other crosses with promising lines.BiotechnologyIn support of breeding activities, molecular markers are currently being used to mapgenes with resistance to tungro from Utri Merah and Utri Rajapan. The molecularmarkers being used are restriction fragment length polymorphism (RFLP), amplifiedfragment length polymorphism (AFLP), and randomly amplified polymorphic DNA(RAPD). Resistance from ARC11554 was mapped earlier (Fig. 2, Sebastian et a11996a, b). Molecular markers tightly linked to the RTSV resistance gene are nowbeing tested for possible use in marker-aided selection (MAS). Cloning of the RTSVresistance gene is also under way (G.O. Romero, personal communication, 1999).26 Sebastian et al
Fig. 1. Scheme for generation advance and screening for tungro resistance.Furthermore, molecular techniques are also being tested in differentiating RTSVstrains in Muñoz, Nueva Ecija, and Midsayap, North Cotabato. This study uses eightdifferential varieties and detects variation in RTSV strains using the reverse transcriptase-polymerasechain reaction technique.Breeding for rice tungro disease 27
Page 2 and 3: RiceTungro DiseaseManagementEdited
Page 4 and 5: ContentsRice tungro disease in the
Page 6 and 7: ForewordThe intensification of rice
Page 8 and 9: PrefaceProviding farmers with optio
Page 10 and 11: Rice tungro disease in the Philippi
Page 12 and 13: Cotabato, and Laguna) during 1995-9
Page 14 and 15: seed growers and farmers to increas
Page 16 and 17: Fig. 2. Incidence of rice tungro di
Page 18 and 19: De los Reyes JB, Cabunagan, RC, Col
Page 20 and 21: Preliminary analysis of genetic var
Page 22 and 23: Fig. 2. Distinct rice tungro bacill
Page 24 and 25: Fig. 4. Dendogram depicting the rel
Page 26 and 27: Preliminary analysis of genetic var
Page 28 and 29: Table 1. Size characteristics of th
Page 30 and 31: varieties and did not seem to exert
Page 32 and 33: Developing breeding lines with RTD
Page 36 and 37: Table 2. Best rice tungro disease-r
Page 38 and 39: Breeding for rice tungro virus resi
Page 40 and 41: Table 2. Promising lines resistant
Page 42 and 43: Table 4. Rice cultivars used as hyb
Page 44 and 45: Shahjahan MB, Jalani S, Zakri AH, I
Page 46 and 47: Table 1. Initial 19 transgenic line
Page 48 and 49: Table 4. Percent infection of trans
Page 50 and 51: very low level. In fact, transgene
Page 52 and 53: of Agricultural Research (ICAR). Pr
Page 54 and 55: Fig. 2. Mean infection with rice tu
Page 56 and 57: (RTBV) and rice tungro spherical vi
Page 58 and 59: Table 4. Percent infection a with r
Page 60 and 61: GLH numbers were much lower on IR62
Page 62 and 63: Cabunagan RC, Hibino H, Sama S, Riz
Page 64 and 65: Prospects of virus-resistant variet
Page 66 and 67: Tungro in Bali (1987-97)Tungro infe
Page 68 and 69: Fig. 5. Proportion of varieties gro
Page 70 and 71: Table 3. Percent incidence of rice
Page 72 and 73: Evaluating rice germplasm for resis
Page 76 and 77: Rice tungro disease resistance andm
Page 80 and 81: ecommended vector-resistant variety
Page 82 and 83: Materials and methodsBatches of ant
Page 84 and 85:
ReferencesClark MF, Adams AN. 1977.
Page 86 and 87:
(e.g., Sokal and Rohlf 1995, p 213;
Page 88 and 89:
Surveillance scheme for tungro fore
Page 90 and 91:
entrusted with implementing the pro
Page 92 and 93:
Table 1. Number of mobile nursery t
Page 94 and 95:
are implemented immediately. The co
Page 96 and 97:
Farmers’ rice tungro managementpr
Page 98 and 99:
Experience with tungroAlthough both
Page 100 and 101:
Table 5. Farmers (%) reporting tung
Page 102 and 103:
Table 7. Farmers’ reported tungro
Page 104 and 105:
Table 9. Mean number (standard devi
Page 106 and 107:
than rice), so they may be reluctan
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Community-based rice pest managemen
Page 110 and 111:
Establishment of farmers’ indigen
Page 112 and 113:
Meanwhile, insects, diseases, and n
Page 114 and 115:
Table 2. Most important diseases fo
Page 116 and 117:
Farmers’ knowledge of pest contro
Page 118 and 119:
ha -1 and above) had a lower RTD in
Page 120 and 121:
Fig. 4. Three major peaks of green
Page 122 and 123:
RBB hill -1 and 4% WSB (Fig. 6). In
Page 124 and 125:
The influence of varietal resistanc
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Limited data exist on how resistant
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tember plantings, reaching 13% and
Page 130 and 131:
Holt J, Chancellor TCB, Reynolds DR
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glh4, respectively. Planting at the
Page 134 and 135:
Results and discussionMinimum unit
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Fig. 4. Transmission efficiency of
Page 138 and 139:
Table 1. Enzyme-linked immunosorben
Page 140 and 141:
Leafhopper control by insecticides
Page 142 and 143:
Fig. 1. Cartoon used for tungro man
Page 144 and 145:
The role of vector control in rice
Page 146 and 147:
To establish relationships between
Page 148 and 149:
Fig. 1. Influence of antifeedants o
Page 150 and 151:
Fig. 4. Tungro incidence before har
Page 152 and 153:
ReferencesAryawan IGN, Widiarta IN,
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Materials and methodsSeedbed protec
Page 156 and 157:
Table 2. Relationship of RTD incide
Page 158 and 159:
Management of rice tungro disease b
Page 160 and 161:
Results and discussionGLH populatio
Page 162 and 163:
Table 4. Field evaluation of foliar
Page 164 and 165:
3.6 to 2.7 t ha -1 . These yields w
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