scholarly journals Use of local rice cultivars as additional differentials to identify pathotypes of Pyricularia oryzae

Bragantia ◽  
2011 ◽  
Vol 70 (4) ◽  
pp. 860-868 ◽  
Author(s):  
Gisele Barata da Silva ◽  
Leila Garcês de Araújo ◽  
Valácia Lemes da Silva Lobo ◽  
Anne Sitarama Prabhu ◽  
Marcela Cristiane Ferreira Rêgo ◽  
...  
Keyword(s):  
Culture Collection ◽  
Pyricularia Oryzae ◽  
Rice Cultivars ◽  
Leaf Blast ◽  
Irrigated Rice ◽  
Resistant Cultivars ◽  
Virulence Pattern ◽  
Bean Research ◽  
Complementary Set ◽  
Pathogenic Diversity

Eight additional rice cultivars as differentials were selected to identify pathotypes occurring in the Tocantins State. They were BRS Jaburu, BRS Taim, BRS Biguá, BR IRGA-417, Epagri 109, Javaé, Metica-1 and Supremo. These differentials were used in addition to the international set to determine the pathogenic diversity of 193 Pyricularia oryzae isolates collected during 1994-2002 from irrigated rice cultivars. They were conserved in Pyricularia culture collection of Embrapa Rice and Bean Research center. From 193 P. oryzae isolates 38 pathotypes were identified based on leaf blast reactions of international set and 29 pathotypes based on these additional differentials. The predominant pathotypes (TI-1, TG-2, TD-15 and TF-2) were represented by 53% of the tested isolates. The major international pathotypes (IB-45, IB-41, II-1 and ID-13) were represented by 43% of the isolates tested. The virulence pattern of 28 isolates belonging to the pathotype IB-45 was further differentiated into nine local pathotypes using additional set of differentials. The irrigated rice cultivars used as additional differentials serve as complementary set to identify pathotypes of interest for breeding blast resistant cultivars for Tocantins State.

scholarly journals Genetic diversity and virulence pattern in field populations of Pyricularia grisea from rice cultivar Metica-1

2002 ◽  
Vol 37 (12) ◽  
pp. 1681-1688 ◽  
Author(s):  
Marta Cristina Filippi ◽  
Anne Sitarama Prabhu ◽  
Leila Garcês de Araújo ◽  
Josias Correa de Faria
Keyword(s):  
Genetic Diversity ◽  
Rice Cultivar ◽  
Pcr Analysis ◽  
Pyricularia Grisea ◽  
Sample Population ◽  
Pathogen Population ◽  
Leaf Blast ◽  
Irrigated Rice ◽  
Virulence Pattern ◽  
Cultivar Specificity

Rice blast is a major yield constraint of the irrigated rice in the State of Tocantins, Brazil. The objective of this investigation was to study the phenotypic and genetic diversity within the pathogen population of Pyricularia grisea in samples collected from four individual farms of rice cultivar Metica-1, under epidemic conditions of leaf blast. A set of 87 isolates was tested on 32 rice genotypes including eight international differentials. Considering 80% similarity in virulence, two groups comprising a total of 81 isolates were recognized, independently of the farms from which they were collected. Eighty percent of the isolates pertained to pathotype ID-14, indicating high cultivar specificity and narrow diversity of virulence in the sample population. The virulence in pathogen population on rice cultivars BR-IRGA 409 and Rio Formoso was low. Analysis of P. grisea isolates using rep-PCR with two primer sequences from Pot2 generated fingerprint profiles of one to nine bands. Cluster analysis revealed the occurrence of six fingerprint groups with similarities ranging from 0.09 to 1. There was no straight relationship between virulence of the isolates based on reaction pattern on 32 genotypes and grouping based on Pot2 rep-PCR analysis of P. grisea isolates collected from 'Metica-1'.

scholarly journals Pathotype diversity of Pyricularia grisea from improved upland rice cultivars in experimental plots

2002 ◽  
Vol 27 (5) ◽  
pp. 468-473 ◽  
Author(s):  
ANNE S. PRABHU ◽  
MARTA C. FILIPPI ◽  
LEILA G. ARAUJO
Keyword(s):  
Grain Quality ◽  
Upland Rice ◽  
Pyricularia Grisea ◽  
Rice Cultivars ◽  
Pathogen Population ◽  
Disease Reaction ◽  
Differential Reaction ◽  
Virulence Pattern ◽  
Pathogenic Diversity ◽  
Experimental Plots

A study was undertaken to examine the pathogenic diversity of Pyricularia grisea isolates retrieved from 14 upland rice (Oryza sativa) cultivars in experimental plots during a period of five years. Inoculations were performed on 32 genotypes with 85 monoconidial isolates under controlled greenhouse conditions. Based on the reaction pattern of eight international differentials, eleven pathotypes of P. grisea were identified. The predominant international races or pathotypes were IB-9 (56.4%), IB-1 (16.4%) and IB-41 (11.8%). A set of eight commercial upland rice cultivars ('Carajás', 'Confiança', 'Maravilha', 'Primavera', 'Progresso', 'Caiapó', 'IAC-47', 'IAC-201') was utilized as additional differentials for describing the virulence pattern of P. grisea. Twenty-six Brazilian pathotypes were identified on the basis of disease reaction on these differentials, in contrast to the 11 international pathotypes. The most predominant Brazilian pathotypes, BB-21 and BB-41 were represented by 28.2% and 17.6% of the isolates tested, respectively. Isolates virulent and avirulent to cultivar 'Primavera' were encountered within the pathotype IB-1. Utilizing Brazilian cultivars as differentials, the 14 isolates of the pathotype IB-1could be further classified into eight local pathotypes, BB-41, BB-13, BB-21, BB-9, BB-29, BB-61, BD-9 and BG-1. Virulence to improved rice cultivars 'Canastra', 'Confiança', 'Carisma', 'Maravilha', 'Primavera' and 'Bonança' was frequent in pathogen population. Some of the Brazilian pathotypes that showed differential reaction on commercial rice cultivars could be utilized for incorporating resistance genes in susceptible cultivars improved for grain quality, by conventional breeding methods.

scholarly journals Phenotypic virulence analysis of Pyricularia grisea isolates from Brazilian upland rice cultivars

2001 ◽  
Vol 36 (1) ◽  
pp. 27-35 ◽  
Author(s):  
Marta Cristina Filippi ◽  
Anne Sitarama Prabhu
Keyword(s):  
Upland Rice ◽  
Pyricularia Grisea ◽  
Rice Cultivars ◽  
Near Isogenic Lines ◽  
Irrigated Rice ◽  
Breeding Sites ◽  
Virulence Analysis ◽  
Early Maturing ◽  
Virulence Pattern ◽  
Degree Of Similarity

Phenotypic virulence analysis was made on population of Pyricularia grisea isolates collected from 10 upland cultivars in three distinct rice breeding sites, with the objective of studying the degree of similarity in the phenotypic virulence among the isolates, the composition of races, and their virulence pattern. Sixteen races were identified based on the reaction type on eight standard international differentials, the predominant ones being IB9 and IB41. The virulence frequency was high on IAC47 and IAC165 among medium and early maturing cultivars, respectively. The frequency of isolates virulent was greater on upland rice cultivars (51.1%) than on irrigated rice cultivars (21.8%). Both virulent and avirulent isolates were present in the population of P. grisea to the known genes in the near isogenic lines. Of72test isolates, 94.4% were virulent for genes Pi3 and Pi4a. Thevirulence frequencies were relatively lower in decreasing order on Pi1, Pi4b and Pi2. Thecoefficient of similarity ranged from 0.28 to1.0 among the isolates pertaining to different races, while within the race IB9, it varied from 0.56 to1.0. Considering the coefficient of similarity of 0.81, 72% of isolates of race IB9 exhibited similar pattern of virulence.

scholarly journals Initial growth and competitive ability of yellow nutsedge and irrigated rice

2013 ◽  
Vol 31 (4) ◽  
pp. 813-821 ◽  
Author(s):  
N.R. Westendorff ◽  
D. Agostinetto ◽  
A.R. Ulguim ◽  
A.C. Langaro ◽  
L. Thürmer
Keyword(s):  
Leaf Area ◽  
Competitive Ability ◽  
Growth Cycle ◽  
Rice Crop ◽  
Initial Growth ◽  
Rice Cultivars ◽  
Replacement Series ◽  
Irrigated Rice ◽  
Yellow Nutsedge ◽  
Dry Biomass

Weeds cause significant reduction in the irrigated rice crop yield. Cyperus esculentus (yellow nutsedge) is adapted to irrigate environment. Information on the competitive ability of the weed to the culture, and their environmental adaptation, are scarce. In this study, we sought to determine the initial growth and competitive ability of yellow nutsedge and irrigated rice, as a function of cultivar growth cycle. Initial growth and competition studies were conducted in a randomized complete design in a greenhouse in the agricultural year 2010/11. For the initial growth study, the treatments consisted of a factorial combination of a biotype of yellow nutsedge and two rice cultivars in the function of the vegetative cycle (BRS Querência: early cycle - IRGA 424: intermediate cycle) and six evaluation times (10, 20, 30, 40, 50, and 60 days after emergence). Were evaluated: plant height, leaf area, aboveground dry biomass and root dry biomass. In the competitive ability study in the replacement series, the cultivar BRS Querência (early cycle) and yellow nutsedge were utilized and tested in different proportions of competition (100:0, 75:25, 50:50, 25:75, and 0:100). Were evaluated leaf area and aboveground dry biomass. In general, rice cultivars have an adaptive value equivalent to yellow nutsedge. IRGA 424 cultivar has less height than weed, becoming the weed control more important in this cultivar. For rice crop, intraspecific competition is more important, whereas for the weed, interspecific competition is the most pronounced.

scholarly journals Morphological Character of Local Irrigated Rice on Farmer Field in North Sulawesi

2018 ◽  
Vol 24 (1) ◽  
pp. 1
Author(s):  
Janne H.W. Rembang ◽  
Abdul W. Rauf ◽  
Joula O.M. Sondakh
Keyword(s):  
Qualitative Method ◽  
Morphological Character ◽  
Grain Morphology ◽  
Morphological Characters ◽  
Leaf Sheath ◽  
Rice Cultivars ◽  
Rice Varieties ◽  
Irrigated Rice ◽  
North Sulawesi ◽  
Leaf Character

<p>Local rice is a potential germplasm as a source of genes that control important properties in rice plants. The research aimed to characterize the morphological character of local rice cultivars of North Sulawesi. The research was conducted from January to June 2015 in North Sulawesi. The method used was the descriptive qualitative method. Exploration was done by collecting samples of local rice cultivars in North Sulawesi. Each cultivar was characterized its morphological characters according to the Characterization and Evaluation Guidelines of Rice Germplasm. The local rice found in North Sulawesi were 10 varieties, namely Pulo Sawah, Superwin, CK, Serwo, Pilihan, Sako, Sito Merah, Sito Putih, TB, and Serayu. There were similarities of the characters from all local rice varieties of North Sulawesi, such as culm (culm strength and culm habit), leaf character (basal leaf sheath color, leaf blade color, collar color, and auricle color), and flower character (panicle exsertion and panicle attitude of branches). The character of grain morphology was very diverse for all local rice varieties of North Sulawesi.</p>

scholarly journals BRS Alvorada and BRSGO Guará irrigated rice cultivars for the states of Goiás and Tocantins

2006 ◽  
Vol 6 (4) ◽  
pp. 318-322 ◽  
Author(s):  
P.H.N. Rangel ◽  
D.M. Soares ◽  
O.P. Morais ◽  
V.A. Cutrim ◽  
J.A. Diniz ◽  
...  
Keyword(s):  
Rice Cultivars ◽  
Irrigated Rice

scholarly journals Effect of Furrow Irrigation on the Severity of False Smut in Susceptible Rice Varieties

Plant Disease ◽  
2010 ◽  
Vol 94 (5) ◽  
pp. 570-574 ◽  
Author(s):  
Steven A. Brooks ◽  
Merle M. Anders ◽  
Kathleen M. Yeater
Keyword(s):  
Agricultural Practices ◽  
Rice Cultivar ◽  
Effective Field ◽  
Field Resistance ◽  
Southern United States ◽  
Rice Cultivars ◽  
Rice Varieties ◽  
Irrigated Rice ◽  
Ustilaginoidea Virens ◽  
False Smut

False smut (Ustilaginoidea virens) is an important emerging disease of rice (Oryza sativa) in the southern United States, where all major rice cultivars and hybrids are susceptible to the disease. False smut susceptibility was evaluated in traditional paddy-rice fields and under furrow-irrigated conditions to determine the effects of alternative agricultural practices on the severity of this disease. Highly effective false smut suppression was observed in furrow-irrigated rice, where the disease was nearly eliminated in susceptible rice entries. False smut suppression was observed for two hybrids and one conventional rice cultivar, demonstrating that suppression was not limited to specific germplasm sources. Kernel smut severity was also monitored, but no effect on this disease was observed from the irrigation treatments. Therefore, suppression of disease severity in nonflooded rice appears to be a phenomenon unique to the rice–false smut pathosystem, which can be exploited to achieve effective field resistance to this disease.

scholarly journals Virulence pattern of Pyricularia grisea isolates from farmers' fields on newly released upland rice cultivars

2005 ◽  
Vol 30 (6) ◽  
pp. 623-628 ◽  
Author(s):  
Leila G. Araújo ◽  
Anne S. Prabhu ◽  
Gisele B. da Silva
Keyword(s):  
Upland Rice ◽  
Specific Resistance ◽  
Pyricularia Grisea ◽  
Rice Cultivars ◽  
Pathogen Population ◽  
Improvement Program ◽  
Breeding Lines ◽  
Virulence Pattern ◽  
Improved Cultivars ◽  
Virulence Frequency

The virulence pattern of the isolates of Pyricularia grisea from commercial fields of the upland rice (Oryza sativa) cultivars 'Primavera' and 'BRS Bonança' was analyzed. A hundred and seventy monoconidial isolates of the pathogen virulent to 'Primavera' and 139 to 'BRS Bonança' collected from eight fields, during two years (2001-2003) were tested, under greenhouse conditions, on six newly released rice cultivars. Differences in virulence pattern were observed in pathogenic populations of 'Primavera' and 'BRS Bonança'. Isolates with virulence to improved cultivars were common in samples from farmers' fields in the absence of aloinfection. The virulence frequency of P. grisea isolates collected from 'Primavera'' to cultivars 'BRS Vencedora', 'BRS Colosso', 'BRS Liderança', 'BRS Soberana', 'BRS Curinga' and 'BRS Talento', was high in descending order. On the other hand, in the fungus population of 'BRS BRS Bonança' virulence frequency was high in 'BRS Talento', followed by 'BRS Curinga', 'BRS Vencedora', 'BRS Liderança', 'BRS Colosso' and 'BRS Soberana'. While virulence to 'BRS Talento' was rare among isolates from 'Primavera', it was most frequent in isolates of 'BRS Bonança'. The six improved rice cultivars permitted to differentiating agriculturally important virulences in the pathogen population which can be utilized in selecting breeding lines for specific resistance, in rice blast improvement program.

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