Genetic control of anthracnose stalk rot resistance in tropical maize

2021 ◽  
Vol 51 ◽  
Author(s):  
Rodrigo Rodrigues Matiello ◽  
Débora da Silva Máximo ◽  
Caroline de Jesus Coelho
Keyword(s):  
Genetic Resistance ◽  
Inbred Lines ◽  
Tropical Maize ◽  
Stalk Rot ◽  
Modern Agriculture ◽  
Support Pillar ◽  
Oligogenic Inheritance ◽  
Parental Lines ◽  
Additive Genetic Effects ◽  
Plot Design

ABSTRACT The genetic resistance to diseases in plants represents an important support pillar in modern agriculture. This study aimed to determine the genetic inheritance to anthracnose stalk rot resistance in tropical maize. Nine segregating families were obtained from contrasting inbred lines crosses. The parental lines and the filial generations (F1, F2, BC1 and BC2) were evaluated for antrachnose stalk rot resistance in an experiment in randomized blocks, with three replications. The treatments were arranged in a split-plot design, with family effect in the plots and generation effect in the split-plots. The results showed a similar inheritance among the families, with predominance of additive genetic effects. The inbreed lines (LR 04-2, LR 03-2 and LR 23-1) were very effective in transmitting resistance genes to their descendants because they allowed sharp decreases in the lesions length in the stalks. It was also possible to notice an oligogenic inheritance involved in the anthracnose stalk rot resistance for the evaluated families. It may be inferred that genetic gains from artificial selection could be successful for developing maize inbred lines more resistant to anthracnose stalk rot.

scholarly journals Diallel analysis of maize resistance to Phaeosphaeria maydis

2004 ◽  
Vol 61 (1) ◽  
pp. 36-42 ◽  
Author(s):  
Herberte Pereira da Silva ◽  
José Roberto Moro
Keyword(s):  
Disease Severity ◽  
Block Design ◽  
Genetic Resistance ◽  
Diallel Analysis ◽  
Inbred Lines ◽  
Randomized Block Design ◽  
Whole Plant ◽  
Sources Of Variation ◽  
Specific Hybrid ◽  
Additive Genetic Effects

In breeding programs directed towards genetic resistance against diseases, the estimation of genetic parameters that control resistance allows the introduction of resistance into suscetible germplasm to be clearly focused. The purposes of this study were to estimate heterosis effects, and the general (GCA) and specific (SCA) combining abilities by using two rating methods for resistance to Phaeosphaeria maydis in a diallel analysis of 36 F1 maize hybrids and their nine inbred lines. Trials were conducted in three environments. Disease severity was evaluated in the whole plant (PI) and in the leaf positioned just below the point of insertion of the main ear (AFA). The trials followed a randomized block design with plots represented by a 5 m long rows. Differences among combining ability estimates for different environments and in both evaluation methods showed significant effects (P < 0.01) for environment (E), GCA, and GCA × E. The SCA, and SCA × E effects were not significant for any of the disease severity variables. The GCA effects were more important than SCA for this set of inbred lines, suggesting that additive genetic effects are the most important sources of variation for this trait. Heterosis effects for resistance were estimated, and it was possible to identify specific hybrid combinations between lines which have high potential for genetic control of this pathogen. Results for both disease severity variables were practically identical, even though the PI method was more convenient to use.

scholarly journals Studies on the Fusarium stalk rot infection of the maize genotypes using the Findex percentage and a computerised image analysis program

2011 ◽  
pp. 45-51
Author(s):  
Csaba Szőke ◽  
István Virág ◽  
Donát Magyar ◽  
Ferenc Rácz ◽  
Csaba L. Marton
Keyword(s):  
Image Analysis ◽  
Natural Infection ◽  
Grain Filling ◽  
Inbred Lines ◽  
Stalk Rot ◽  
Maize Genotypes ◽  
Accurate Picture ◽  
Computerised Image Analysis ◽  
Continental Climate ◽  
Plot Design

In a continental climate, the pathogens causing the most serious problems are species belonging to the Fusarium genus. When the pathogen attacks the stalk, the plant dies earlier, reducing grain filling and resulting in small, light ears. In addition, the stalks break or lodge, resulting in further yield losses from ears that cannot be harvested. During the three years of the experiment, 14 inbred lines were examined. The genotypes were sown in a two-factor split-plot design with four replications, with the genotypes in the main plots and four treatments in the subplots: two Fusarium graminearum isolates (1. FG36, 2. FGH4), 3. sterile kernels, 4. untreated control. The results experiments showed significant differences between the genotypes for resistance to fusarium stalk rot. Among the inbred lines the best resistance to fusarium stalk rot was exhibited by P06 and P07, both of which were related to ISSS. The precision and sensitivity of disease evaluations carried out visually and using image analysis software were compared in the experiment, and with two exceptions the CV values were lower for the image analysis. As the CV for measurements can be considered as a relative error, it can be stated that image analysis is the more precise of the two methods, so this technique gives a more accurate picture of the extent of stalk rot. The extent of stalk rot developing in response to natural infection is extremely environment-dependent, so the use of artificial inoculation is recommended for selection trials. 

Genotypic variation and relationships among traits for root morphology in a panel of tropical maize inbred lines under contrasting nitrogen levels

Euphytica ◽  
2019 ◽  
Vol 215 (3) ◽  
Author(s):  
Lívia Gomes Torres ◽  
Diego Gonçalves Caixeta ◽  
Wemerson Mendonça Rezende ◽  
Andreia Schuster ◽  
Camila Ferreira Azevedo ◽  
...  
Keyword(s):  
Root Morphology ◽  
Genotypic Variation ◽  
Inbred Lines ◽  
Tropical Maize ◽  
Nitrogen Levels ◽  
Maize Inbred Lines

scholarly journals Phenotypic and molecular characterization of a set of tropical maize inbred lines from a public breeding program in Brazil

BMC Genomics ◽  
2022 ◽  
Vol 23 (1) ◽  
Author(s):  
Sirlene Viana de Faria ◽  
Leandro Tonello Zuffo ◽  
Wemerson Mendonça Rezende ◽  
Diego Gonçalves Caixeta ◽  
Hélcio Duarte Pereira ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Population Structure ◽  
Inbred Lines ◽  
Breeding Program ◽  
Tropical Maize ◽  
Maize Breeding ◽  
Breeding Programs ◽  
The Public ◽  
Maize Inbred Lines

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.

scholarly journals Effect of mancozeb on the control of mycosphaerella blight of field pea

2000 ◽  
Vol 80 (2) ◽  
pp. 403-406 ◽  
Author(s):  
T. D. Warkentin ◽  
A. G. Xue ◽  
D. W. McAndrew
Keyword(s):  
Yield Loss ◽  
Foliar Application ◽  
Genetic Resistance ◽  
Similar Efficacy ◽  
Field Trials ◽  
Field Pea ◽  
Mycosphaerella Pinodes ◽  
Western Canada ◽  
Flowering Stage ◽  
Plot Design

Mycosphaerella blight (MB) [Mycosphaerella pinodes (Berk. & Blox.)Vestergr.] causes substantial yield loss to field pea in western Canada in most seasons and is a disease for which genetic resistance is lacking. The objective of this research was to evaluate the effectiveness of foliar application of mancozeb for the control of MB of field pea. Field trials of split-plot design were conducted at two sites per year from 1996 to 1998 in southern Manitoba, with cultivars as main-plots and fungicide treatments as sub-plots. In most site-years, a single application of mancozeb at the early flowering stage was effective in reducing MB severity and in increasing yield. Mancozeb had similar efficacy to chlorothalonil, the only currently registered fungicide for control of MB in field pea. The beneficial effect of both fungicides was greater for the highly MB susceptible cultivars AC Tamor and Carrera than the moderately MB susceptible cultivar Radley. Key words: Pisum sativum, field pea, mycosphaerella blight, mancozeb, chlorothalonil

scholarly journals Morpho-physiological traits associated with heat stress tolerance in tropical maize (Zea mays L.) at reproductive stage

2019 ◽  
Vol 13 ((04) 2019) ◽  
pp. 536-545 ◽  
Author(s):  
Jewel Jameeta Noor ◽  
M.T. Vinayan ◽  
Shahid Umar ◽  
Pooja Devi ◽  
Muhammad Iqbal ◽  
...  
Keyword(s):  
Heat Stress ◽  
Grain Yield ◽  
Stress Tolerance ◽  
Inbred Lines ◽  
Physiological Traits ◽  
Optimal Temperature ◽  
Tropical Maize ◽  
Important Trait ◽  
Heat Stress Tolerance ◽  
Secondary Traits

Heat stress resilience has emerged as an important trait in maize hybrids targeted for post–monsoon spring cultivation in large parts of South Asia and many other parts of the tropics. Selection based on grain yield alone under heat stress is often misleading, and therefore an approach involving stress-adaptive secondary traits along with grain yield could help in the development of improved, stable heat stress tolerant cultivars. We attempted to identify reliable and effective secondary traits associated with heat stress tolerance in tropical maize and sources of heat stress tolerant germplasm. A panel of 99 elite maize inbred lines representing the wider genetic diversity of tropical maize and a set of 58 elite hybrids were phenotyped under natural heat stress and optimal temperature for grain yield and 15 secondary traits including 10 morpho-physiological traits and 5 yield attributes. Evaluation under natural heat stress was done during the spring season by adjusting the planting date so that the complete reproductive stage (from tassel emergence to late grain filling) was exposed to heat stress. The optimal temperature trial was planted during the monsoon season with no exposure to heat stress at any crop stage. Heat stress significantly affected most of the observed traits. Among the traits studied two yield attributing traits, i.e.- ears per plant (EPP) and kernel per row (KPR), and three morpho-physiological traits, i.e.- chlorophyll content (CC), leaf firing (LF) and tassel blast (TB) were found to be the key secondary traits associated with grain yield under heat stress. In addition, low anthesis-silking internal (ASI) is an important trait that needs to be added in the index selection for heat stress tolerance. The study identified nine promising heat stress tolerant maize inbred lines with desirable secondary traits and grain yield under severe heat stress, which could be used as source germplasm in heat stress tolerance maize breeding program.

scholarly journals Potential in a collection of adapted and exotic tropical maize inbred lines as resistance source for stem borers

2018 ◽  
Vol 10 (8) ◽  
pp. 183-190 ◽  
Author(s):  
Olaitan Oloyede-Kamiyo Qudrah ◽  
Oyewole Ajala Sam ◽  
Oluwatoyosi Job Anthony
Keyword(s):  
Inbred Lines ◽  
Tropical Maize ◽  
Stem Borers ◽  
Maize Inbred Lines ◽  
Resistance Source
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