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Search Results: 1 - 10 of 50549 matches for " Y Sere "
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Identification of Near-Isogenic lines Resistance to Rice Yellow Mottle Virus
A Jaw, MN Ndjionndjop, R Akromah, Y Sere
African Crop Science Journal , 2012,
Abstract: Rice yellow mottle virus (RYMV) is a serious disease in rice production in the lowland and irrigated ecologies. A study was conducted to examine the resistance of rice (Oryza sp.) lines RYMV. One hundred near-isogenic lines (NILs) from BC2F7 population derived from cross combination: Gigante (Oryza indica cv.) x IR64, Gigante x FK28 and Gigante x IR47 were evaluated. Twenty NILs were identified to be resistant to RYMV BF27 isolate from phenotypic screening. Enzyme-Linked-immunosorbent assay (ELISA) test revealed 36 lines to be resistant to RYMV with low virus content. Foreground selection using the gene marker, revealed 22 lines showed introgression of rymv1-2 allele. On the average, 71% of the markers used in the evaluation showed polymorphism. The highest proportion of recurrent parental contribution was obtained from the cross Gigante x IR64; and the lowest from Gigante x IR47. Individuals from Gigante x FK28 had the highest percentage of the donor parent (70%) and Gigante x IR64 had the lowest value but showed the highest genomic proportion of the recurrent parent (57%) was showed by Gigante x IR64.
Etude de la résistance au flérien de ligneées inter-et intraspécifiques de riz de bas-fonds en conditions d'infestation artificielles
SI Ouedraogo, I Somda, I Wonni, Y Sere
African Crop Science Journal , 2007,
Abstract: Le riz (Oryza sativa) est une nourriture de base importante au Burkina Faso. Cependant, la productivité de riz au Burkina Faso est affectée par l’infestation bactérienne de flanche menant à l’échec total de récolte dans beaucoup des cas. Il y a donc urgence d’évaluer et par la suite introduire des cultivars résistants pour toutes les zones écologiques du Burkina faso. Dans cette étude, cette évaluation de la résistance à la flanche bactérienne a été faite en utilisant soixante- neuf lignées de riz des basses terres, dont huit lignées intra spécifiques et soixante et interspécifiques. Une variante de Xanthomonas oryzae pv. oryzae du Burkina Faso a été utilisé pour tester les lignées candidates. Une variante de référence (NCPPB 1150) a été obtenue au Danemark et de l’eau distillée a été utilisée respectivement comme le contr le positif et négatif. La variété susceptible à la bactérie flanche, la variété chinoise TCS 10 et la résistante FKR19 ont été aussi utilisées comme contr le. L’expérience a été conduite en serre à la température de 28-30°C et 12 heures de cycle de lumière. La conception expérimentale était du type split plot avec trois réplications. Apres quinze jours les vieilles plantes de riz ont été vaccinées et les sympt mes de maladie ont été observés quatorze jours après l’inoculation. Les résultats ont indiqué que 55.07 % des lignées sont résistantes, 23.20 % modérément résistant, 5.80 % modérément susceptible, 7.24 % susceptible et 8.69 % extrêmement susceptible. Il a été aussi observé que 78.68 % de lignées interspécifiques étaient plus résistantes en comparaison avec 75 % d’intra spécifiques. La variante bactérienne de Bagre (Burkina Faso) était plus virulente que le NCPPB de référence 1150. Les lignées inter spécifiques et intra spécifiques doivent être essayé dans les conditions de champ avant la recommandation pour l’adoption dans les zones infestées par Xanthomonas oryzae pv. oryzae.
Existence of Two Pathotypes of Rice Yellow mottle virus, Genus Sobemovirus, in Mali
A. Onasanya,Y. Sere,M. Sie,K. Akator
Plant Pathology Journal , 2006,
Abstract: Screenhouse studies were conducted using 10 RYMV isolates from 6 different localities in Mali against 8 WARDA differential rice genotypes to investigate the possible existence and classification of different pathotypes of RYMV in Mali. The reaction of 8 rice genotypes to the 10 RYMV isolates was different in terms of SPAD and yield reductions. The interaction between isolates and rice cultivar was also significant. AMMI cluster analysis revealed the existence of two pathotypes (HPI and MPI) of RYMV isolates in Mali. Of 8 rice genotypes studied, only Bouake 189 was highly susceptible to the two pathotypes. This information could be useful in the rice breeding programs aiming at deployment of RYMV resistant genotypes to different rice ecologies and localities in Mali.
Regional Yield Evaluation of the Interspecific Hybrids (O. glaberrimax O. sativa) and Intraspecific (O. sativa x O. sativa) Lowland Rice
M. Sie,Y. Sere,S. Sanyang,L.T. Narteh
Asian Journal of Plant Sciences , 2008,
Abstract: The immense potential of the lowlands in West and Central Africa for durable intensification of rice cropping have not been realised due to biotic and abiotic constraints. There is a need to replace existing rice varieties with others that are better adapted to the lowland conditions. After the success of the upland interspecific varieties, Africa Rice Center (WARDA) and its partners developed NERICA varieties suitable for irrigated and rainfed lowlands. The stable varieties resulting from this work were evaluated under preliminary yield trials in eight countries at 19 sites. The entries included 61 interspecific (O. glaberrima x O. sativa indica) varieties and 9 intraspecific (O. sativa indica x O. sativa indica) varieties. The aim of the study is to introduce new lowland NERICAs through a participatory approach and to identify ideotypes that are adapted to lowland conditions. Variations did exist among the 73 rice varieties with respect to the five traits that were evaluated. Total number of tillers, panicle number and flowering dates were observed to greatly influence the yield among the 73 varieties that were evaluated. A principal components plot clustering analysis were used to group the accessions. The interspecific varieties formed the most interesting group and have a better capacity for adaptation to the diversity of lowlands. They have acceptable yields, sometimes higher than those of intraspecific varieties and checks. Thus, most lowland NERICAs varieties tested in three ecologies could produce more than 5 t ha-1. The results obtained were quite encouraging and showed that, the varieties possess good agronomic traits that are well adapted to intensified lowland rice farming. The recent naming of some of these interspecific varieties as NERICA-L (New Rice for Africa Lowland) by Africa Rice Center has confirmed that they compare well with the traditional varieties. Thus, from this study, we now have a new set of interspecific varieties that are adapted to lowland conditions and which the national research programs can use in various tests for satisfying farmers` needs.
Rice Bacterial Leaf Blight in West Africa: Preliminary Studies on Disease in Farmers` Fields and Screening Released Varieties for Resistance to the Bacteria
Y. Sere,A. Onasanya,V. Verdier,K. Akator
Asian Journal of Plant Sciences , 2005,
Abstract: As little information is available in Africa on Xanthomonas oryzae pv. oryzae, a highly destructive pathogen of rice, and its relationship with released rice varieties, a disease survey and samplings were carried out in Niger, Burkina Faso and Mali which indicated a wide spread of Bacterial Leaf Blight (BLB) in farmers` fields. Sixty pure BLB isolates cultures were obtained. Pathogenicity of 4 Malian isolates against four important rice varieties revealed differences in pathogenicity among isolates and in resistance of the varieties tested. The results obtained in these initial studies revealed the future research directions to increasing rice production in West Africa.
Identification and Differentiation of Three Nigerian Orseolia sp. by RAPD Markers
F.E. Nwilene,A. Onasanya,O. Okhidievbie,Y. Sere
Asian Journal of Plant Sciences , 2006,
Abstract: Identification and differentiation of three Nigerian Orseolia sp. (Orseolia nwanzei, Orseolia bonzii and Orseolia oryzivora) was carried out using Random Amplified Polymorphic DNA (RAPD) markers. Ninety operon primers were screened, from which 6 showed polymorphism among the three species tested, generating 54 bands, 69% of which were polymorphic with sizes ranging between 1000 and 3000 bp. DNA fingerprints of adults and pupae of each species were genetically identical. O. oryzivora and O. bonzii are identified as most closely related, while O. nwanzei is distinct. The DNA fingerprints identified for each Orseolia sp. will be useful for entomological survey for the identification of new species within the context of the effective development of rice cultivars with durable resistance to AfRGM.
Reactions and Resistance Status of Differential Rice Genotypes to Rice Yellow Mottle Virus, Genus Sobemovirus in Cote d`Ivoire
A. Onasanya,Y. Sere,F. Nwilene,M.E. Abo
Asian Journal of Plant Sciences , 2004,
Abstract: High yielding rice genotypes with good levels of resistance to RYMV were identified at Africa Rice Center-WARDA in Cote d`Ivoire. The yields and resistance stability of these genotypes, however, remain uncertain. The performance of 13 genotypes over 10 different RYMV isolates from 7 localities in Cote d`Ivoire was tested in the screenhouse. Chlorophyll (SPAD) and yield reductions due to RYMV disease were evaluated. Considerable diversity was observed in the reactions of these genotypes to all the RYMV isolates. Percentage yields and SPAD reduction were between 2.3-90.3 and 5.3-40%, respectively. Of 13 rice genotypes studied, IR 47686-15-1-1(P) had the lowest mean SPAD and yield reductions. The levels of resistance shown by japonicas were better than those of indicas. Six genotypes (FARO 11; GIGANTE (tete); H 232-44-1-1; IR 47686-15-1-1(P); IR 47686-15-1-1; ITA 235) could be described as possessing both stable and acceptable levels of resistance to RYMV. The high genotype by environment interactions in the reactions of the rice genotypes to RYMV suggests the possible existence of different strains of RYMV in Cote d`Ivoire. This information could be useful in rice breeding programs aiming at deployment of RYMV resistant genotypes to different rice ecologies and localities in Cote d`Ivoire.
Serological Differentiation Indices and Phylogenetic Analysis ofRice yellow mottle virus Isolates in Cote d`Ivoire
Y. Sere,A. Onasanya,K. Akator,A. Afolabi
Journal of Biological Sciences , 2007,
Abstract: Serological diversity of 178 RYMV isolates was determined by phylogenetic analysis of Serological Differentiation Indices (SDI) data generated from antigen coated-plate enzyme-linked immunosorbent assay (ACP-ELISA) using 26 RYMV Polyclonal antisera. These RYMV isolates were obtained from northern, southern, eastern and western Cote d`Ivoire. All the RYMV isolates was classified into three main serogroups (Sg1, Sg2 and Sg3) and six subgroups (Sg1a, Sg1b, Sg2a, Sg2b, Sg3a and Sg3a). This indicates the existence and levels of serodiversity among RYMV isolates in Cote d`Ivoire. These results provide evidence of a possible relationship between serological property, host plant and ecological origin of RYMV isolates. Phylogenetic classification of each RYMV isolate defined by SDI data in ACP-ELISA is potentially useful in epidemiological studies to assess isolate identity and interaction as well as to assist breeding programs aiming at the development of cultivars with durable resistant to RYMV in Cote d`Ivoire.
Genetic analysis of Resistance to Rice Bacterial blight in Uganda
I Habarurema, G Asea, J Lamo, P Gibson, R Edema, Y Sere, RO Onasanya
African Crop Science Journal , 2012,
Abstract: Rice bacterial blight (Xanthomonas oryzae pv.oryzae) is a major constraint to rice (Oryza sativa L.) production in Uganda and as part of strategies to develop resistant cultivars, it is important to evaluate resistance of commonly used cultivars. A full-diallel mating design involving three resistant and three susceptible rice cultivars was used to produce F1 and F2 progenies in a screen-house at the National Crop Resources Research Institute (NaCRRI), Namulonge in Uganda. The parents and F2 populations were challenged with the Xanthomonas oryzae pv.oryzae isolate (UX00) and lesion lengths were scored 21 days after inoculation (DAI). Griffing’s combining ability analysis showed significant specific combining ability (SCA) and non-significant general combining ability (GCA) effects, indicating the preponderance of non-additive gene effects in controlling the resistance to bacterial leaf blight (BLB) in rice. Rice genotypes, NERICA14, NERICA10 and NERICA4 had desirable GCA estimates, and were, therefore, the best general combiners. Crosses CO39 x NERICA10 and NERICA14 x IRAT104 had favorable SCA values. These hybrids are thus, promising in developing the BLB resistant progenies. Significant reciprocal effects indicate the importance of maternal contribution in controlling the BLB virulence. For this, resistant lines can be used as female parents for fear of affecting transfer of resistance to the progenies, and the hybrids and their reciprocals would be handled separately. Low estimates of narrow sense coefficient of genetic determination (NSCGD) (0.9%) and medium broad sense coefficient of genetic determination (BSCGD) estimates (16.4%) highlight the influence of non-additive gene action in controlling the resistance to BLB, confirming an effective selection of superior genotypes at advanced generations when the maximum homozygosity is fixed.
Diversity of the Rice Blast Pathogen Populations in Ghana and Strategies for Resistance Management
S.K. Nutsugah,J.K. Twumasi,J. Chipili,Y. Sere
Plant Pathology Journal , 2008,
Abstract: The present study describes the outputs of a collaborative research programme funded by the UK`s Department for International Development-Crop Protection Program to investigate the genetic (lineages) and pathogenic (pathotypes) diversity of the blast fungus populations and characterize the key sites suitable for resistance screening. Seventy-one Magnaporthe grisae isolates were collected from seven regions where rice is grown, representing blast populations in Ghana. Following molecular characterization, these isolates were grouped into four distinct lineages designated as GH-1, GH-2, GH-3 and GH-4 and 25 pathotypes. GH-1 was the major lineage comprising 52% of all the isolates and was present across the country on up to 24 rice cultivars. GH-2 comprising of 30% of the isolates sampled was restricted in distribution mainly from Hohoe area on up to seven cultivars. GH-3 consisted of six isolates from Western, Eastern and Central Regions while GH-4 consisted of two isolates from Nyankpala in Northern Region. Occurrence of blast pathogen on wild rice and weed hosts has been observed and their potential impact needs to be considered in blast/weed management. Baseline data new to Ghana on the diversity and distribution pattern of the blast pathogen populations have been established and key sites identified. Adaptive research is continuing to develop technologies suitable for long-term pathogen monitoring, identify sources of resistance and develop appropriate blast management strategies.
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