Rice tungro disease management - IRRI books - International Rice ...

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Breeding for rice tungro virus resistancein IndonesiaA.A. Daradjat, N. Widiarta, and A. HasanuddinBreeding for rice tungro resistance is one of the major objectives of therice breeding program in Indonesia. Early studies were directed towarddeveloping rice varieties with good plant type, high yield, and resistance tothe green leafhopper (GLH) vector. In recent work, the breeding objectiveswere redefined to consider two additional traits: grain quality and resistanceto tungro viruses. A vigorous hybridization program involving severalcultivars with high yield, good plant type, excellent grain quality, and resistanceto tungro viruses was implemented. From the initial work, severalhigh-yielding rice varieties with resistance to GLH have been released. Preliminaryresults from this study indicated that 2,296 accessions have strongresistance to tungro viruses. Based on the range of infection rates withtungro on single-cross populations, it was observed that Utri Merah, TjempoKijik, Seratus Hari T36, and M1085c-10-1 were effective donors of tungroresistance. Membramo was the best combiner of the donor cultivars, withhigh yield and excellent grain quality. The reaction of advanced breedinglines to tungro infection varied with disease pressure and vector populationin the area.Rice tungro disease caused by rice tungro spherical virus (RTSV) and rice tungrobacilliform virus (RTBV) results in considerable losses in rice production in someirrigated ecosystems in Indonesia. Between 1968 and 1984, the disease damaged anestimated 199,000 ha of rice (Manwan et al 1985).In 1995, 12,340 ha of rice in Surakarta regency, Central Java, were severelyinfected, causing yield losses of about US$1.87 million (Anonymous 1995). Continuousand staggered planting of susceptible cultivars such as Cisadane and IR64and climatic conditions favorable for both the leafhopper vector and the disease todevelop were among the factors that favored the epidemics.Improved crop production technology that consists of improved cultivars, appropriatecultural practices, and suitable pest management is expected to reduce losses.In pest outbreaks, the use of resistant cultivars was observed to be the most effectivecontrol measure in Indonesian ecosystems. Thus, breeding for resistance to pestsand diseases was included as one of the main activities in the breeding program. Thispaper briefly reviews the efforts that have been made in developing rice cultivarsresistant to tungro disease in Indonesia.Early activitiesEarly resistance breeding work at the Central Research Institute for Food Crops identifiedtraits associated with virus resistance, such as growth habit, yield, and insectvector resistance.It was confirmed that tungro disease is transmitted by the green leafhopper( Nephotettix virescens ). This information led to the adoption of rice cultivars resistant
to green leafhopper as a strategy for reducing tungro disease incidence. Therefore,efforts to reduce losses due to tungro disease focused on developing rice varietiesresistant to GLH.Screening methodThe effects of the vector on tungro incidence were studied by field screening in LanrangExperimental Farm, South Sulawesi. Twenty-one- or 25-day-old seedlings were exposedto natural infection by tungro through GLH infestation in the field. Seedlingswere transplanted as two 10-hill rows at a spacing of 30 × 20 cm. To ensure adequateinoculum pressure, single rows of the susceptible check (TN1) were transplantedevery 10 rows and in the surrounding field 2 wk before transplanting test seedlings.Land preparation, fertilizer application, and hand weeding were done as recommended.No pesticides were applied at any stage of plant growth.Screening resultsUp to 1986, 47, 503 genotypes had been evaluated. Of these. 6,864 lines were classifiedas resistant and 8,432 as moderately resistant (Table 1). Table 2 lists some of thepromising lines resistant to tungro disease. Selections from crosses involving thesepromising lines have been released as new improved cultivars (Table 3).The data in Table 3 indicate that, if a single resistant cultivar of rice is growncontinuously in a particular area where there is year-round irrigation, the plant resistancelevel will be reduced due to the adaptation of the GLH population to the host.Continuous cropping of such GLH-resistant cultivars could increase the selectionTable 1. Rice breeding lines with resistance, moderate resistance, moderate susceptibility,and susceptibility to tungro disease in Indonesia, 1974-86.YearLines tested Plant reaction a Lines failed(no.)(no.)R MR MS S1974-751975-761976-771977-781978-791979-801980-811981-821982-831983-841984-851985-86Total4,8231,9071,6647,6224,3144,1916,0834,0275,5851,2722,7532,81247,053975335788143218111,4382331,303145913216,8647852262801,3675529541,5619311,1451151703468,4328842883451,3891,1241,7371,6821,1501,1818535443910,6851,4584158252,7471,7186891,4027141,8861831,2211,25814,5167216431361,30559900999717449174486,583a R = resistant, MR = moderately resistant, MS = moderately susceptible, S = susceptible, Source:Anonymous 1988.32 Daradjat et al
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 34 and 35: In CES, 28 entries had low tungro i
Page 36 and 37: Table 2. Best rice tungro disease-r
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
Page 108 and 109:
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
Page 126 and 127:
Limited data exist on how resistant
Page 128 and 129:
tember plantings, reaching 13% and
Page 130 and 131:
Holt J, Chancellor TCB, Reynolds DR
Page 132 and 133:
glh4, respectively. Planting at the
Page 134 and 135:
Results and discussionMinimum unit
Page 136 and 137:
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,
Page 154 and 155:
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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