Abstract
Due to their potential applications for food safety, there is a growing interest in rice root-associated microbial communities, but some systems remain understudied. Here, we compare the ...assemblage of root-associated microbiota in rice sampled in 19 small farmer's fields from irrigated and rainfed lowlands in Burkina Faso, using an amplicon metabarcoding approach of the 16S rRNA gene (prokaryotes, three plant samples per field) and ITS (fungi, one sample per field). In addition to the expected structure by root compartments (root vs rhizosphere) and geographical zones, we showed that the rice production system is a major driver of microbiome structure. In irrigated systems, we found a higher diversity of prokaryotic communities from the rhizosphere and more complex co-occurrence networks, compared to rainfed lowlands, while fungal communities exhibited an opposite pattern (higher richness in rainfed lowlands). Core taxa were different between the two systems, and indicator species were identified: mostly within Bacillaceae in rainfed lowlands, and within Burkholderiaceae and Moraxellaceae in irrigated areas. Finally, a higher abundance in rainfed lowlands was found for mycorrhizal fungi (both compartments) and rhizobia (rhizosphere only). Our results highlight deep microbiome differences induced by contrasted rice production systems that should consequently be considered for microbial engineering applications.
Irrigated rice and rainfed lowlands harbor contrasted root-associated microbiomes in small farmer's fields from Burkina Faso, with contrasted richness, and peculiar indicator taxa in each system.
In recent years, Brown spot disease of rice (BSR) has been observed on leaves and seeds of rice in all rice-growing areas of Burkina Faso.
and
are the main fungal species isolated from BSR infected ...tissues and they are frequently observed in the same field. However, we are lacking information on the genetic diversity and population structure of these fungi in Burkina Faso. The mode of reproduction is also unknown. The genetic diversity of isolates of
(n=61) and
(n=151), collected from major rice-growing areas of Burkina Faso, was estimated using genotyping-by-sequencing (GBS). The mean values for nucleotide diversity (π) were 1.9 x10
for
and 4.8 x10
for
. There is no genetic differentiation between the geographical populations of each species. The analysis of molecular variance revealed that 89% and 94% of the genetic variances were within the populations of
and
, respectively. For each species, four genetic clusters were identified by two clustering methods (DAPC and sNMF). The distribution of these genetic groups was independent of the geographical origin of the isolates. Evidence of recombination was detected in the populations of
and
For
balanced mating type ratios were supporting sexual reproduction. For
overrepresentation of MAT1-2 isolates (79%) suggested a predominant asexual reproduction. This study provides important information on the biology and genetics of the two major fungi causing brown spot disease of rice in Burkina Faso.
Rice blast caused by Magnaporthe oryzae is one of the major rice diseases in Burkina Faso with losses up to 77% under favorable disease conditions. For the management of this disease, the use of ...resistant cultivars remains the most economical, and most protective method for the environment. This study focuses on the evaluation of the resistance of 49 lines of rice resulting from crosses between popular cultivars of different countries of Sub-Sahara against blast. The experimental design used is a 7 x 7 Alpha lattice with 3 repetitions. The study was conducted in two rainfed sites (Farako-Bâ and Karfiguela) and two irrigated sites (Bagré and Tengrela) in Burkina Faso. The results showed that the rice genotypes developed the disease differently depending on their developmental stages and rice growing systems. In rainfed rice cultivation, 32 genotypes were resistant to leaf blast and 3 (AR-67, IR 130412 and CSR 36) were resistant to leaf and panicle blast. In irrigated conditions, 44 genotypes were resistant to leaf blast and 6 (TZLR-74, IR 133136-B, NERICA 4, NERICA 10, NERICA 11 and CSR 36) were resistant to leaf and panicle blast. The genotype (CSR 36) was disease resistant in both ecological conditions. The results of this study will make it possible to choose the best rice cultivars, tolerant or resistant to blast, and to identify the effective resistance genes in their genomes.
How to Cite: Abalo Itolou KASSANKOGNO. Fatimata Hourétou DIALLO, Adama ZONGO, et. al., 2023. "Performance Evaluation of 49 Rice Lines with Known Rice Blast Resistance Genes in Irrigated and Rain-Fed Areas." Journal of Agriculture and Crops, vol. 10, pp. 20-29.
Rice blast, caused by the filamentous ascomycete Pyricularia oryzae, is one of the most devastating diseases of rice. Four genetic clusters were previously identified and three have a large ...geographic distribution. Asia is the center of diversity and the origin of most migrations to other continents and sexual reproduction persisted only in the South China-Laos-North Thailand region, which was identified as the putative center of origin of all P. oryzae populations on rice. Despite the importance of rice blast disease, little is known about the diversity and the population structure of the pathogen in Africa (including Madagascar). The present study was aimed at describing the structure of African populations of P. oryzae and identifying the relationship between African and worldwide genetic clusters. A set of 2057 strains (including 937 African and 1120 Madagascan strains) were genotyped using 12 SSR markers to assess the diversity and the population structure of P. oryzae. Four genetic clusters were identified in Africa and Madagascar. All the four clusters previously identified are present in Africa. Populations from West Africa, East Africa and Madagascar are highly differentiated. The geographic structure is consistent with limited dispersion and with some migration events between neighboring countries. The two mating types are present in Africa with a dominance of Mat1.2 but no female fertile strain was detected supporting the absence of sexual reproduction on this continent. This study showed an unsuspected high level of genetic diversity of P. oryzae in Africa and suggested several independent introductions.
Multiple constraints affect rice yields in West Africa. Among these constraints are viral, bacterial, and fungal pathogens. We aimed to describe the spatiotemporal patterns of occurrence and ...incidence of multiple rice diseases in farmers' fields in contrasting rice growing systems in the western Burkina Faso. For this purpose, we selected a set of three pairs of sites, each comprising an irrigated area and a neighboring rainfed lowland, and studied them over four consecutive years. We first performed interviews with the rice farmers to better characterize the management practices at the different sites. This study revealed that the transplanting of rice and the possibility of growing rice twice a year are restricted to irrigated areas, while other practices, such as the use of registered rice cultivars, fertilization, and pesticides, are not specific but differ between the two rice growing systems. Then, we performed symptom observations at these study sites to monitor the following four diseases: yellow mottle disease, Bacterial Leaf Streak (BLS), rice leaf blast, and brown spot. The infection rates were found to be higher in irrigated areas than in rainfed lowlands, both when analyzing all observed symptoms together (any of the four diseases) and when specifically considering each of the two diseases: BLS and rice leaf blast. Brown spot was particularly prevalent in all six study sites, while yellow mottle disease was particularly structured geographically. Various diseases were frequently found together in the same field (co-occurrence) or even on the same plant (coinfection), especially in irrigated areas.
The objective of this study was to evaluate, in a semi-controlled environment, the resistance of twelve (12) new rice genotypes (KBR2, KBR4, KBR6, KBR8, KBR9, KBRll, KBR12, KBR13, KBR15, KBR17, ...KBR28, KBR42) to rice blast caused by Magnaporthe oryzae in Burkina Faso. The experimental design used was a randomised block with three (03) replications. The parameters assessed were leaf and panicle severity, leaf and panicle incidence, yield per pot and percentage yield loss. The results showed that genotypes KBRll, KBR15 and KBR42 were resistant to medium resistance to blast, with values ranging from 7.7% to 15% of leaf area diseased and from 14% to 24.07% of panicles diseased. These genotypes recorded the best yields per pot of 60.32g/pot, 65.97g/pot and 60.43g/pot respectively, with relatively low yield losses. Genotypes KBRll, KBR15 and KBR42 were resistant to medium resistance to leaf and panicle blast with high yield performance and relatively low yield loss rates. These genotypes can be used to control rice blast in rice fields in Burkina Faso. They therefore need to be improved and made more widely available. This will require the support of agricultural research, extension services and farm advisory services.
L’anthracnose est l’une des principales maladies fongiques du sorgho au Burkina Faso. La présente étude porte sur l’évaluation des performances agronomiques de 11 variétés de sorgho et de leur ...comportement vis-à-vis de l’anthracnose l’Ouest du Burkina Faso. Le dispositif expérimental utilisé est un bloc de Fisher complètement randomisé en 3 répétitions et 14 traitements correspondant aux variétés. Le matériel végétal utilisé a été constitué de 3 lignées et de 11 hybrides de sorgho provenant respectivement du Burkina Faso et du Brésil. L’analyse phytosanitaire des graines a été réalisée, selon la méthode du papier buvard. Les résultats ont montré que les hybrides ESFOEHN et KALATUR ont été les plus précoces. La lignée SARIASSO11 a enregistré la plus grande hauteur, tandis que les hybrides ISQ223, KALATUR et ESFOEHN ont été semi naines. Les hybrides ISQ223 et BRG71098 ont enregistrés, respectivement, les rendements le plus élevé (4590 kg/ha) et le plus faible (1711 kg/ha). Les variétés ISR329, MSP332 et SARIASSO11 ont été les plus résistantes à l’anthracnose, cependant, les variétés ESFOEHN et KALATUR ont été les plus sensibles. L’analyse phytosanitaire des graines, issues des variétés testées, a révélé la présence de Alternaria alternata, Exserohilium rostratum, Aspergilus sp, Rhizopus sp, Drechslera sp et Colletotrichum graminicola. Selon les performances agronomiques et le comportement des différentes variétés à l’anthracnose, quatre groupes ont été identifiés. Des corrélations positives ont été obtenues entre la longueur des panicules et le rendement(r=0,55), entre le taux d’infection des semences au Colletotrichum graminicola et la sévérité de l’anthracnose (r=0,52) et entre la sévérité et incidence de l’anthracnose (r=0,92). Les résultats de cette étude peuvent servir de base pour le choix des variétés de sorgho performantes et résistantes à l’anthracnose au Burkina Faso.
Anthracnose is one of the main fungal diseases of sorghum in Burkina Faso. The present study focuses on the evaluation of agronomic performance of sorghum varieties and their behaviour towards anthracnose in western of Burkina Faso. The experiments were laid out in a randomized complete block design with 3 replications and 14 treatments corresponding to the varieties. The plant material used consisted of 3 sorghum lines and 11 hybrids from Burkina Faso and Brazil respectively. Phytosanitary analysis of seeds was carried out using the blotting paper method. The results showed that ESFOEHN and KALATUR hybrids were the earliest. The SARIASSO11 line recorded the greatest height while ISQ223, KALATUR and ESFOEHN hybrids were semi-dwarf. The hybrids ISQ223 and BRG71098 had the highest (4590 kg/ha) and lowest (1711 kg/ha) yields respectively. Varieties ISR329, MSP332 and SARIASSO11 were the most resistant to anthracnose, while ESFOEHN and KALATUR were the most susceptible. Health analysis of seeds from tested varieties revealed the presence of Alternaria alternata, Exserohilium rostratum, Aspergilus sp, Rhizopus sp, Drechslera sp and Colletotrichum graminicola. According to agronomic performance and the behaviour of varieties to anthracnose, four groups were identified. Also, positive correlations were obtained between panicle length and yield (r=0.55), seed infection rate with Colletotrichum graminicola and anthracnose severity (r=0.52) and between anthracnose severity and incidence (r=0.92). The results of this study could serve as a basis for selection of efficient and anthracnose-resistant sorghum varieties in Burkina Faso.
La présente étude porte sur l’évaluation des performances agronomiques des variétés de sorgho et leur comportement vis-à-vis de l’anthracnose à l’Ouest du Burkina Faso. Le dispositif expérimental ...utilisé est un bloc de Fisher complètement randomisé en 3 répétitions et 14 traitements correspond aux variétés. Le matériel végétal utilisé était constitué de 3 lignées et 11 hybrides de sorgho provenant respectivement du Burkina Faso et du Brésil. L’analyse phytosanitaire des graines a été réalisée selon la méthode du papier buvard. Les résultats ont montré que les hybrides ESFOEHN et KALATUR ont été les plus précoces. La lignée SARIASSO11 a enregistré la plus grande hauteur tandis que les hybrides ISQ223, KALATUR et ESFOEHN ont été semi naines. Les hybrides ISQ223 et BRG71098 ont enregistrés respectivement les rendements le plus élevé (4590 kg/ha) et le plus faible (1711 kg/ha). Les variétés ISR329, MSP332 et SARIASSO11 ont été les plus résistantes à l’anthracnose, cependant les variétés ESFOEHN et KALATUR ont été les plus sensibles. L’analyse phytosanitaire des graines issues des variétés testées a révélé la présence de Alternaria alternata, Exserohilium rostratum, Aspergilus sp, Rhizopus sp, Drechslera sp et Colletotrichum graminicola. Selon les performances agronomiques et le comportement des variétés à l’anthracnose, quatre groupes ont été identifiés. Des corrélations positives ont été obtenues entre la longueur des panicules et le rendement(r=0,55), entre le taux d’infection des semences au Colletotrichum graminicola et la sévérité de l’anthracnose (r=0,52) et entre la sévérité et incidence de l’anthracnose (r=0,92). Les résultats de cette étude servent de base pour le choix des variétés de sorgho performantes et résistantes à l’anthracnose au Burkina Faso.
Blast, caused by Magnaporthe oryzae B.C.Couch, is the main fungal disease in the rice fields in Burkina Faso. Three pure essential oils at different concentrations of Cymbopogon schoenanthus, Ocimum ...americanum and Lippia multiflora, and four of their combinations were tested in vitro to evaluate their inhibition properties on mycelial growth, sporulation, and spore germination of M. oryzae. The contact method and the fumigation method were used for the different tests at doses of 0.05 μl/ml, 0.1 μl/ml, 0.3 μl/ml, 0.6 μl/ml, 0.9 μl/ml, 1.2 μl/ml, 1.5 μl/ml, 1.8 μl/ml, 2.1 μl/ml and 2.4 μl/ml. Two chemical fungicides, mancozeb and azoxystrobin and an absolute control were used in the trials. The results showed that the pure essential oil of L. multiflora and its combination with that of C. schoenanthus presented the most effective minimum doses of inhibition in the contact and fumigation method. These doses ranged from 0.1 μl/ml to 0.3 μl/ml for 100% inhibition of radial growth, sporulation, and spore germination of Magnaporthe oryzae. Mancozeb inhibited 100% of all parameters evaluated, while azoxystrobin was ineffective. The essential oil of L. multiflora and its combination with that of C. schoenanthus can be tested in a real environment to control rice blast.
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