scholarly journals Identification of Resistance to Maize rayado fino virus in Maize Inbred Lines

Plant Disease ◽  
2013 ◽  
Vol 97 (11) ◽  
pp. 1418-1423 ◽  
Author(s):  
Jose Luis Zambrano ◽  
David M. Francis ◽  
Margaret G. Redinbaugh

Maize rayado fino virus (MRFV) causes one of the most important virus diseases of maize in America. Severe yield losses, ranging from 10 to 50% in landraces to nearly 100% in contemporary cultivars, have been reported. Resistance has been reported in maize populations, but few resistant inbred lines have been identified. Maize inbred lines representing the range of diversity in the cultivated types and selected lines known to be resistant to other viruses were evaluated to identify novel sources of resistance to MRFV. The virus was transmitted to maize seedlings using the vector Dalbulus maidis, and disease incidence and severity were evaluated beginning 7 days postinoculation. Most of the 36 lines tested were susceptible to MRFV, with mean disease incidence ranging from 21 to 96%, and severity from 1.0 to 4.3 (using a 0 to 5 severity scale). A few genotypes, including CML333 and Ki11, showed intermediate levels of resistance, with 14 and 10% incidence, respectively. Novel sources of resistance, with incidence of less than 5% and severity ratings of 0.4 or less, included the inbred lines Oh1VI, CML287, and Cuba. In Oh1VI, resistance appeared to be dominant, and segregation of resistance in F2 plants was consistent with one or two resistance genes. The discovery of novel sources of resistance in maize inbred lines will facilitate the identification of virus resistance genes and their incorporation into breeding programs.

BMC Genomics ◽  
2022 ◽  
Vol 23 (1) ◽  
Author(s):  
Sirlene Viana de Faria ◽  
Leandro Tonello Zuffo ◽  
Wemerson Mendonça Rezende ◽  
Diego Gonçalves Caixeta ◽  
Hélcio Duarte Pereira ◽  
...  

Abstract Background The characterization of genetic diversity and population differentiation for maize inbred lines from breeding programs is of great value in assisting breeders in maintaining and potentially increasing the rate of genetic gain. In our study, we characterized a set of 187 tropical maize inbred lines from the public breeding program of the Universidade Federal de Viçosa (UFV) in Brazil based on 18 agronomic traits and 3,083 single nucleotide polymorphisms (SNP) markers to evaluate whether this set of inbred lines represents a panel of tropical maize inbred lines for association mapping analysis and investigate the population structure and patterns of relationships among the inbred lines from UFV for better exploitation in our maize breeding program. Results Our results showed that there was large phenotypic and genotypic variation in the set of tropical maize inbred lines from the UFV maize breeding program. We also found high genetic diversity (GD = 0.34) and low pairwise kinship coefficients among the maize inbred lines (only approximately 4.00 % of the pairwise relative kinship was above 0.50) in the set of inbred lines. The LD decay distance over all ten chromosomes in the entire set of maize lines with r2 = 0.1 was 276,237 kb. Concerning the population structure, our results from the model-based STRUCTURE and principal component analysis methods distinguished the inbred lines into three subpopulations, with high consistency maintained between both results. Additionally, the clustering analysis based on phenotypic and molecular data grouped the inbred lines into 14 and 22 genetic divergence clusters, respectively. Conclusions Our results indicate that the set of tropical maize inbred lines from UFV maize breeding programs can comprise a panel of tropical maize inbred lines suitable for a genome-wide association study to dissect the variation of complex quantitative traits in maize, mainly in tropical environments. In addition, our results will be very useful for assisting us in the assignment of heterotic groups and the selection of the best parental combinations for new breeding crosses, mapping populations, mapping synthetic populations, guiding crosses that target highly heterotic and yielding hybrids, and predicting untested hybrids in the public breeding program UFV.


2019 ◽  
Vol 30 (1) ◽  
pp. 25-33
Author(s):  
E.A. Rossi ◽  
M. Ruiz ◽  
M. Di Renzo ◽  
N.C. Bonamico

CIMMYT maize inbred lines (CMLs) are freely distributed to breeding programs around the world. Better information on phenotypic and genotypic diversity may provide guidance to breeders on how to use more efficiently the CMLs in their breeding programs. In this study a group of 291 CIMMYT maize inbred lines, was phenotyped by nine agro-morphological traits in south Córdoba, Argentina and genotyped using 18,082 SNPs. Based on the geographic information and the environmental adaptation, 291 CMLs were classified into eight subgroups. Anthesis-silking interval (IAE) was the trait with higher phenotypic diversity. A 40% of maize inbred lines, with IAE less than five days, show a good adaptation to growing conditions in south Córdoba, Argentina. The low phenotypic variation explained by environmental adaptation subgroups indicates that population structure is only a minor factor contributing to phenotypic diversity in this panel. Principal component analysis (ACP) allowed us to obtain phenotypic and genotypic orderings. Generalized procrustes analysis (APG) indicated a 60% consensus between both data type from the total panel of maize lines. In each environmental adaptation subgroup, the APG consensus was higher. This result, which might indicate linkage disequilibrium between SNPs markers and the genes controlling these agro-morphological traits, is promising and could be used as an initial tool in the identification of Quantitative Trait Loci (QTL). Information on genetic diversity, population structure and phenotypic diversity in local environments will help maize breeders to better understand how to use the current CIMMYT maize inbred lines group. Key words: broad-sense heritability, multivariate analysis, SNPs, agro-morphological traits.


Author(s):  
Maizura Abu Sin ◽  
Ghizan Saleh ◽  
Nur Ashikin Psyquay Abdullah ◽  
Pedram Kashiani

Genetic diversity and phenotypic superiority are important attributes of parental inbred lines for use in hybrid breeding programs. In this study, genetic diversity among 30 maize (Zea mays L.) inbred lines comprising of 28 introductions from the International Maize and Wheat Improvement Center (CIMMYT), one from Indonesia and a locally developed, were evaluated using 100 simple sequence repeat (SSR) markers, as early screening for potential parents of hybrid varieties. All markers were polymorphic, with a total of 550 unique alleles detected on the 100 loci from the 30 inbred lines. Allelic richness ranged from 2 to 13 per locus, with an average of 5.50 alleles (na). Number of effective alleles (ne) was 3.75 per locus, indicating their high effectiveness in revealing diversity among inbred lines. Average polymorphic information content (PIC) was 0.624, with values ranging from 0.178 to 0.874, indicating high informativeness of the markers. High gene diversity was observed on Chromosomes 8 and 4, with high number of effective alleles, indicating their potential usefulness for QTL analysis. The UPGMA dendrogram constructed identified four heterotic groups within a similarity index of 0.350, indicating that these markers were able to group the inbred lines. The three-dimensional PCoA plot also supports the dendrogram grouping, indicating that these two methods complement each other. Inbred lines in different heterotic groups have originated from different backgrounds and population sources. Information on genetic diversity among the maize inbred lines are useful in developing strategies exploiting heterosis in breeding programs


2016 ◽  
Vol 2 (2) ◽  
pp. 45 ◽  
Author(s):  
Marcia Bunga Pabendon ◽  
M. Dahlan ◽  
Sutrisno Sutrisno ◽  
M. L.C. George

<p class="p1">Information on genetic relationships among available crop germplasm such as maize inbred lines, has important implications to breeding programs. A set of 26 maize inbreds togeher with six standard lines from CIMMYT (CML51, CML292, CML202, CML206, CML236, dan CML396), was characterized using 26 SSR markers, which were coverage of the maize genomes. The objective of this study was to analyze genetic diversities among the Indonesian maize inbred collections. Polymorphism Information Content (PIC) value and the observed genetic distance indicated the existence of large variabilities among the inbreds. Cluster analysis based on 27% of the Jaccard’s similarity coefficient placed the inbreds into three groups. Genetic distances among all the possible pairs without the standard maize lines varied from 0.32 (KSX360F2-5-1-3-1v vs KSX2601F2-5-1-1-v) to 0.88 (PT963298-1-B-B-Bv vs Mr13). Cluster and Principal Coordinate Analysis of the genetic distances, revealed a clear differentiation of the inbred lines into groups according to their source populations. This clustering were consistent with those of the known pedigree records of the inbreds based on their morphological characters. These results support the use of morphological traits in the production of maize hybrids. The SSR markers proved to be effective to characterize, identify, and demonstrate genetic similarities among the maize inbred lines.</p>


2017 ◽  
Vol 18 (2) ◽  
pp. 87-90 ◽  
Author(s):  
Gerald J. Seiler ◽  
Christopher G. Misar ◽  
Thomas J. Gulya ◽  
William R. Underwood ◽  
Bradley C. Flett ◽  
...  

Sclerotinia basal stalk rot (BSR) is a serious fungal disease that reduces yield of global sunflower (Helianthus annuus L.) production. Because limited chemical and biological controls of BSR are available and the present-day hybrids lack sufficient resistance, identification of new sources of resistance is needed to manage the disease in the future. A total of 59 cultivated oilseed sunflower accessions from the Agricultural Research Council, Grain Crops Institute, Potchefstroom, South Africa sunflower collection were evaluated for resistance to BSR in artificially inoculated field trials. Nine accessions from the South African sunflower collection were identified with a disease incidence less than or equal to the moderately resistant sunflower oilseed hybrid. These lines can be used in breeding programs to introgress the genes for resistance to Sclerotinia BSR into other adapted lines, providing a more efficient, durable, and environmentally friendly host plant resistance.


2014 ◽  
Vol 2 (4) ◽  
pp. 213-222 ◽  
Author(s):  
Xiaoming Wang ◽  
Yunhua Zhang ◽  
Xiude Xu ◽  
Hongjie Li ◽  
Xiaofei Wu ◽  
...  

1981 ◽  
Vol 32 (5) ◽  
pp. 741 ◽  
Author(s):  
DM Persley ◽  
IF Martin ◽  
RS Greber

Maize inbred lines, derived from both Australian and exotic sources, and used in a breeding programme at Kairi, Qld, were screened for resistance to a Johnson grass strain of sugarcane mosaic virus (SCMV-Jg). There was a good correlation between ratings made following manual inoculation in a glasshouse and those following exposure to natural field infection. Seven lines were highly resistant in both glasshouse and field ratings. A further nine lines showed an intermediate level of resistance following manual inoculation and developed from 0 to 7 % infection under field conditions when a susceptible line developed 99 % infection. Data obtained following the manual inoculation of plants in segregating generations of crosses between resistant KL 57 and susceptible KL 9 were consistent with resistance being controlled by a single dominant gene. Six lines (Pa 405, CI 44, Tx 601, Oh 07, Oh 7B, 38-11) that were used as sources of resistance to maize dwarf mosaic virus, strain A (MDMV-A) in the U.S.A. developed natural infection levels of less than 15% with SCMV-Jg. Only Pa 405 was highly resistant to manual inoculation. Four of 11 SCMV-Jg resistant lines were also highly resistant to manual inoculations with the sugarcane, Sabi grass and Queensland blue couch grass strains.


Plant Disease ◽  
1998 ◽  
Vol 82 (5) ◽  
pp. 555-559 ◽  
Author(s):  
D. E. Kyle ◽  
C. D. Nickell ◽  
R. L. Nelson ◽  
W. L. Pedersen

Phytophthora rot, caused by Phytophthora sojae, is a damaging disease of soybean (Glycine max (L.) Merr.) throughout the soybean-producing regions of the world. The discovery of new sources of resistance in soybean is vital in maintaining control of Phytophthora rot, because races of the pathogen have been discovered that can attack cultivars with commonly used resistance genes. The objectives of this study were to investigate the distribution and diversity of Phytophthora-resistant soybean in southern China and identify sources that confer resistance to multiple races for implementation into breeding programs. Soybean accessions obtained from southern China were evaluated for their response to races 1, 3, 4, 5, 7, 10, 12, 17, 20, and 25 of P. sojae using the hypocotyl inoculation technique in the greenhouse at Urbana, Illinois in 1996 and 1997. Accessions were identified that confer resistant responses to multiple races of the pathogen. These accessions may provide sources of resistance for control of Phytophthora rot of soybean in the future. The majority of the accessions with resistance to eight or more of the ten races tested were from the provinces of Hubei, Jiangsu, and Sichuan in southern China. Based on the evaluated accessions, these provinces appear to be valuable sources of Phytophthora-resistant soybean.


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