scholarly journals Screening Oryza Species Plants for Rice Sheath Blight Resistance

Plant Disease ◽  
2002 ◽  
Vol 86 (7) ◽  
pp. 808-812 ◽  
Author(s):  
G. C. Eizenga ◽  
F. N. Lee ◽  
J. N. Rutger
Keyword(s):  
Sheath Blight ◽  
Oryza Species ◽  
Growth Chamber ◽  
Lesion Length ◽  
Cultivated Rice ◽  
Visual Rating ◽  
Leaf Lesion ◽  
Generation Progeny ◽  
Limited Scale ◽  
Moderately Resistant

Rice wild relatives, Oryza species, are one possible source of sheath blight (Rhizoctonia solani) resistance genes. However, Oryza spp. cannot be screened in the field as is done for cultivated rice (O. sativa) because the plant canopy does not favor disease development and many plants drop mature seed. Thus, a growth chamber-greenhouse method of screening Oryza spp. and their early generation progeny is needed. Primary-secondary and ratoon tillers of rice cultivars-germplasm which ranged from moderately resistant to very susceptible were evaluated first for sheath blight susceptibility. Plants were inoculated by placing R. solani-colonized toothpicks at the leaf collar, then incubating plants in a growth chamber. After 7 days, plants were visually rated for sheath blight severity, and the lesion length of each leaf was measured. Ranking of cultivar-germplasm susceptibility by visual rating of primary-secondary tillers corresponded to the ranking from field ratings. Visual ratings correlated best with combined lesion length of the second and third leaves. For ratoon tillers, visual ratings correlated best with second-leaf lesion length. Next, this method was used with ratoon tillers to evaluate sheath blight susceptibility of 21 Oryza spp. accessions and F1 progeny from crosses between 17 accessions and cultivated rice. This method proved useful on a limited scale for screening germplasm that could not be evaluated under field conditions.

scholarly journals Rice Sheath Blight Disease Resistance Identified in Oryza spp. Accessions

Plant Disease ◽  
2008 ◽  
Vol 92 (11) ◽  
pp. 1503-1509 ◽  
Author(s):  
B. Prasad ◽  
G. C. Eizenga
Keyword(s):  
Soft Drink ◽  
Petri Dish ◽  
Sheath Blight ◽  
Potato Dextrose Agar ◽  
Growth Chamber ◽  
Cultivated Rice ◽  
Sheath Blight Disease ◽  
Agar Plug ◽  
Initiation Stage ◽  
Blight Disease

Oryza spp., wild relatives of cultivated rice (Oryza sativa), may contain novel resistance genes for sheath blight, caused by Rhizoctonia solani, that could be used to enhance resistance to this important disease in commercial rice. To identify resistant sources for sheath blight disease, 73 Oryza genotypes were evaluated with three different methods conducted in the greenhouse, growth chamber, or laboratory because there are significant limitations to screening wild Oryza spp. under field conditions. For the microchamber method, 4-week-old seedlings were inoculated with a potato dextrose agar plug containing mycelia, covered with a 2-liter soft drink bottle, and rated 1 week after inoculation. A detached-leaf method involved placing a potato dextrose agar plug containing mycelia on the abaxial surface of a leaf section that was cut from a 5-week-old plant and placed on moist filter paper in a petri dish under constant light, then evaluated after 72 h. For the toothpick inoculation method, toothpicks colonized with mycelia were placed in the leaf collar region of plants at the panicle initiation stage, plants were placed in a growth chamber, and disease symptoms were evaluated after 7 days. The microchamber method gave a more uniform, reproducible response, and was easier to use under greenhouse conditions. Seven Oryza spp. accessions were identified as moderately resistant with three accessions classified as O. nivara (IRGC104705, IRGC100898, and IRGC104443) and one each as O. barthii (IRGC100223), O. meridionalis (IRGC105306), O. nivara/O. sativa (IRGC100943), and O. officinalis (IRGC105979).

scholarly journals Genetic diversity analysis in indigenous rice (Oryza sativa L.) germplasm for Bacterial Leaf Blight (Xanthomonas oryzae pv. Oryzae) using resistance genes linked markers

2021 ◽  
Author(s):  
Khannetah K. R . ◽  
Ramchander S. ◽  
Andrew Peter Leon M. T ◽  
Shobha D. ◽  
Saravanan S. ◽  
...  
Keyword(s):  
Oryza Sativa ◽  
Resistance Genes ◽  
Bacterial Blight ◽  
Rice Yield ◽  
Oryza Sativa L ◽  
Molecular Data ◽  
Lesion Length ◽  
R Genes ◽  
Leaf Clipping ◽  
Moderately Resistant

Abstract Among rice ( Oryza sativa L.) diseases, bacterial blight (BB), caused by Xanthomonas oryza pv. Oryzae , plays a pivotal role in decreasing rice yield. BB is reported to be the most serious constraint to improving rice yield. The present investigation assessed the potentiality of bacterial blight resistance and molecular characterization of 100 rice accessions for four major BB resistance genes, viz., Xa4, xa5, xa13 and Xa21 . Disease screening was carried out under glasshouse conditions using a BB culture isolated from BB-infected rice fields through the leaf clipping method. Analyses of 13 BB resistance genes linked with polymorphic microsatellites markers indicated the presence of single-, two-, three- and four-gene combinations of xa5, xa13, Xa4 and Xa21 . We found four accessions to be resistant; 34 accessions to be moderately resistant; 49 accessions to be moderately susceptible and 13 accessions to be susceptible. Among the resistant lines, IR12L110, Namcheonbyeo, Dhalaheera and SahbhagiDhan recorded a minimum lesion length of 3.7cm, 4.2cm, 4.67cm and 8.3 cm, respectively. Phylogenetic tree, constructed using molecular data, grouped the rice germplasm into four major clusters. R genes xa 5 and Xa4 contributed 14 positive compatible R genes, each belonging to 28 germplasm for BB resistance. The potential genetic resources identified as resistant to BB can be used as donors for the improvement of rice BB resistance in rice breeding programs.

scholarly journals Standardization of inoculation techniques for sheath blight of rice caused by Rhizoctonia solani (Kuhn)

2019 ◽  
Vol 48 (4) ◽  
pp. 1107-1113
Author(s):  
Santosh Kumar ◽  
Md Nadeem Akhtar ◽  
Erayya ◽  
Tribhuwan Kumar
Keyword(s):  
Rice Variety ◽  
Foliar Spray ◽  
Relative Number ◽  
Sheath Blight ◽  
Lesion Length ◽  
Inoculum Sources ◽  
Soil Inoculation ◽  
Inoculation Techniques ◽  
Disease Rating ◽  
Mycelial Suspension

To develop a simple and reliable inoculation technique using inoculum sources viz., mycelial suspension, mycelial ball, sclerotia and soil inoculation with homogenized mycelia suspension was carried out. The efficiency of different inoculation techniques were tested on susceptible rice variety Rejendra Sweta. Sheath inoculation with sclerotia gave lesion length 10.33 and 12.33 cm after seven and 15 days of inoculation, respectively. It also shows more significance in terms of relative lesion height to plant height i.e. 30.06 % followed by soil inoculation with homogenized mycelial suspension i.e. 21.62 %. However, relative number of lesions as compared to control was found to be maximum (429.18%) in mycelial suspension spray, followed by soil inoculation using homogenized mycelia suspension (400.43%). The disease rating of sheath blight of rice was also found to be maximum (5) in sheath inoculation with sclerotia followed by soil inoculation of mycelial suspension (3). The disease rating was minimum (1) in sheath inoculation with mycelial ball and foliar spray with mycelial suspension.

scholarly journals The Role of Antioxidant Enzymes in Adaptive Responses to Sheath Blight Infestation under Different Fertilization Rates and Hill Densities

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Wei Wu ◽  
Xuejie Wan ◽  
Farooq Shah ◽  
Shah Fahad ◽  
Jianliang Huang
Keyword(s):  
Antioxidant Enzymes ◽  
Rice Cultivar ◽  
Sheath Blight ◽  
Planting Density ◽  
Lesion Length ◽  
Adaptive Responses ◽  
Block Method ◽  
Sod Activity ◽  
Agar Block ◽  
Mda Content

Sheath blight of rice, caused byRhizoctonia solani, is one of the most devastating rice diseases worldwide. No rice cultivar has been found to be completely resistant to this fungus. Identifying antioxidant enzymes activities (activity of superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT)) and malondialdehyde content (MDA) responding to sheath blight infestation is imperative to understand the defensive mechanism systems of rice. In the present study, two inoculation methods (toothpick and agar block method) were tested in double-season rice. Toothpick method had greater lesion length than agar block method in late season. A higher MDA content was found under toothpick method compared with agar block method, which led to greater POD and SOD activities. Dense planting caused higher lesion length resulting in a higher MDA content, which also subsequently stimulated higher POD and SOD activity. Sheath blight severity was significantly related to the activity of antioxidant enzyme during both seasons. The present study implies that rice plants possess a system of antioxidant protective enzymes which helps them in adaptation to sheath blight infection stresses. Several agronomic practices, such as rational use of fertilizers and optimum planting density, involved in regulating antioxidant protective enzyme systems can be regarded as promising strategy to suppress the sheath blight development.

USE OF THE EXCISED SHOOT ASSAY TO EVALUATE RESISTANCE TO Phytophthora cactorum OF APPLE ROOTSTOCK CULTIVARS

1988 ◽  
Vol 68 (3) ◽  
pp. 851-857 ◽  
Author(s):  
R. S. UTKHEDE ◽  
H. A. QUAMME
Keyword(s):  
Malus Domestica ◽  
Root Rot ◽  
Crown Rot ◽  
Lesion Length ◽  
Malus Domestica Borkh ◽  
Root Stock ◽  
P 16 ◽  
The Mean ◽  
Crown And Root Rot ◽  
Moderately Resistant

The excised shoot assay was used to evaluate crown and root rot (P. cactorum (Leb & Cohn) Schroeter) resistance of several apple (Malus domestica Borkh.) rootstock cultivars using relative lesion length as a measure of resistance. To determine the best time to assess crown rot resistance, three cultivars, M.26 (moderately resistant), MM.111 (moderately susceptible) and MM.106 (susceptible) were tested monthly for a 12-mo period. The best separation of the three cultivars of known resistance was from the period of February to June and again in November. In another test on 27 apple root-stock cultivars tested quarterly, good separation of known standards was achieved only on the April sampling date. In both tests the organism appeared to overwhelm resistance of the tissue during the most active stage of shoot growth in July and August. Based on the mean for the three dates (April, October and January) the cultivars P. 16, J9, P.2, M.4, 0.3, P.1, M.9, M.26, P.22 and P.18 were significantly more resistant than the field-susceptible rootstocks, MM.106. None was significantly more resistant than M.9 and M.4, the resistant standards.Key words: Crown rot, Malus domestica Borkh, root rot, P. cactorum, rootstocks, apple

Screening of Rice (Oryza sativa L.) Genotypes for Sheath Blight (Rhizoctonia solani) in changing Climate Scenario

2016 ◽  
Vol 3 (2) ◽  
Author(s):  
SUBHASH CHANDRA ◽  
Pankaj Kumar ◽  
Neelam Yadav
Keyword(s):  
Oryza Sativa ◽  
Rhizoctonia Solani ◽  
Oryza Sativa L ◽  
Climate Scenario ◽  
Sheath Blight ◽  
Changing Climate ◽  
Resistant Reaction ◽  
Moderately Resistant

Out of 108 germplasm, screened under natural as well as under artificial inoculated condition, none of the entries were found immune or resistant. However, forty five entries viz., Ramkajra, Baigani black, Beni, Prasada, Narendra-118, Narendra-97, Aswani, madhuri, Sawani, IET-14807, Pant Dhan-11, Gajgour, IET-16711, Karahni, Dalkachari, Bagri, Rambli-AS, Motiforam, Ram bhog, Kaland, Aktahwa -R, Lalkawa, Tulsi, IR-36, Suggapankhi, IET-16706, basti cul-9, Aktahwa- FIO, CR-1446, Sonachoor, Aktahwa, Bansfool, Saket-4, IR-24, NDR-359, NDR-637, Pant Dhan-4, NDR- 330, Gajgour, T-182, IET-16705, Pusa-33, Akasi, IR-8, Saryukushmaha were found moderately resistant, 37 moderately susceptible and fourteen were observed susceptible. Rest of the entries showed highly susceptible reaction. Under artificial inoculated condition, out of 82 entries, none of the entry was found resistant. Only two entries viz., Baigani black and Prasada showed moderately resistant reaction, seventeen moderately susceptible and twenty seven entries susceptible. Rest of the entries was found highly susceptible.

Interrelationships of Oryza species based on electrophoretic patterns of alcohol dehydrogenase

1992 ◽  
Vol 70 (2) ◽  
pp. 352-358 ◽  
Author(s):  
Anil Grover ◽  
Deepak Pental
Keyword(s):  
Alcohol Dehydrogenase ◽  
Oryza Rufipogon ◽  
Band Pattern ◽  
Oryza Species ◽  
Oryza Glaberrima ◽  
Cultivated Rice ◽  
Major Band ◽  
Electrophoretic Patterns ◽  
Oryza Punctata ◽  
Germinating Seeds

Nineteen different species belonging to the genus Oryza were studied for variation in electrophoretic patterns of alcohol dehydrogenase (ADH) extracted from germinating seeds. The ADH patterns were similar for aerobically and anaerobically germinating seeds of all the species. Oryza saliva accessions, both indica and japonica, revealed a five-band pattern on polyacrylamide gels. African cultivated rice, Oryza glaberrima, had an alcohol dehydrogenase pattern similar to that of O. sativa. Oryza perennis complex comprising of Oryza nivara, Oryza rufipogon in Asia, Oryza barthii, Oryza longistaminata in Africa, and some of the accessions of O. rufipogon from America had ADH patterns similar to that of O. sativa. In a few accessions of O. rufipogon from America, only three bands were visualized. Oryza minuta, Oryza officinalis, Oryza punctata, Oryza alta, Oryza grandiglumis, and Oryza latifolia had similar patterns with one major band at the same Rf value as the major band of O. sativa and two minor bands corresponding to the two bands found in O. sativa. Oryza australiensis, Oryza brachyantha, and Oryza granulata had distinct patterns. Oryza ridleyi had a six-band pattern with three major and three minor bands. The three major bands correspond to the major band of O. granulata, O. officinalis, and O. australiensis. Based on alcohol dehydrogenase data, six major groups were identified amongst Oryza species. Key words: Oryza species, alcohol dehydrogenase, phylogenetics.

scholarly journals Quantification of the Components of Resistance to Rice Sheath Blight Using a Detached Tiller Test Under Controlled Conditions

Plant Disease ◽  
2011 ◽  
Vol 95 (12) ◽  
pp. 1507-1515 ◽  
Author(s):  
Laetitia Willocquet ◽  
Jagjeet S. Lore ◽  
S. Srinivasachary ◽  
Serge Savary
Keyword(s):  
Defense Mechanisms ◽  
Sheath Blight ◽  
Survival Duration ◽  
Lesion Length ◽  
Relative Role ◽  
Sources Of Resistance ◽  
Rice Varieties ◽  
Components Of Resistance ◽  
Controlled Conditions ◽  
Physiological Resistance

Resistance of rice (Oryza sativa) to sheath blight, caused by Rhizoctonia solani, is quantitative and involves two mechanisms: physiological resistance and disease escape. The epidemiological concept of components of resistance was applied using a detached tiller method under controlled conditions, to specifically address physiological resistance to sheath blight in rice. A sclerotium was inserted below the leaf collar of individual rice tillers maintained in tubes filled with water. Different variables were measured after incubation: number of lesions, lesion length, vertical sheath colonization, presence or absence of dark margin at the edge of lesions, and survival duration of the leaf blade. Several rice varieties reported to have different levels of susceptibility to sheath blight were assessed, together with varieties that are cultivated over large areas. Although numerical differences between rice varieties were observed for all disease variables, only the number of lesions significantly differed among varieties tested in this study. The varieties Pecos and IR64 had the consistently lowest and highest disease intensities, respectively. This methodology may allow the detection of sources of resistance that specifically involve defense mechanisms. When combined with field assessment, this methodology should also enable to quantitatively assess the relative role of both mechanisms of resistance to sheath blight.

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