Evaluation of Maize Inbred Lines for Resistance to Fusarium Ear Rot and Fumonisin Accumulation in Grain in Tropical Africa

Fusarium ear rot and fumonisin contamination is a major problem facing maize growers worldwide, and host resistance is the most effective strategy to control the disease, but resistant genotypes have not been identified. In 2003, a total of 103 maize inbred lines were evaluated for Fusarium ear rot caused by Fusarium verticillioides in field trials in Ikenne and Ibadan, Nigeria. Disease was initiated from natural infection in the Ikenne trial and from artificial inoculation in the Ibadan trial. Ear rot severity ranged from 1.0 to 6.0 in both locations in 2003. Fifty-two inbred lines with disease severity ≤3 (i.e., ≤ 10% visible symptoms on ears) were selected and reevaluated in 2004 for ear rot resistance, incidence of discolored kernels, and fumonisin contamination in grain. At both locations, ear rot severity on the selected lines was significantly (P < 0.0020) higher in 2004 than in 2003. The effects of selected inbred lines on disease severity were highly significant at Ikenne (P = 0.0072) and Ibadan (P < 0.0001) in 2004. Inbred lines did not affect incidence of discolored kernels at both locations and across years except at Ikenne (P = 0.0002) in 2004. Similarly, significant effects of inbred lines on fumonisin concentration were observed only at Ikenne (P = 0.0201) in 2004. However, inbred lines 02C14585, 02C14593, 02C14603, 02C14606, 02C14624, and 02C14683 had consistently low disease severity across years and locations. Fumonisin concentration was significantly correlated with ear rot only at Ikenne (R = 0.42, P < 0.0001). Correlation between fumonisin concentration and incidence of discolored kernels was also significant at Ikenne (R = 0.39, P < 0.0001) and Ibadan (R = 0.35, P = 0.0007). At both locations, no significant inbred × year interaction was observed for fumonisin concentration. Five inbred lines, namely 02C14585, 02C14603, 02C14606, 02C14624, and 02C14683, consistently had the lowest fumonisin concentration in both trials. Two of these inbred lines, 02C14624 and 02C14585, had fumonisin levels <5.0 μg/g across years in trials where disease was initiated from both natural infection and artificial inoculation. These lines that had consistently low disease severity are useful for breeding programs to develop fumonisin resistant lines.

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Resistance in Maize Inbred Lines to Fusarium verticillioides and Fumonisin Accumulation in South Africa

Plant Disease ◽

10.1094/pdis-08-11-0695 ◽

2012 ◽

Vol 96 (6) ◽

pp. 881-888 ◽

Cited By ~ 26

Author(s):

I. M. Small ◽

B. C. Flett ◽

W. F. O. Marasas ◽

A. McLeod ◽

M. A. Stander ◽

...

Keyword(s):

South Africa ◽

Fusarium Verticillioides ◽

Field Trials ◽

Inbred Lines ◽

Fusarium Ear Rot ◽

Ear Rot ◽

Maize Breeding ◽

Sources Of Resistance ◽

Breeding Lines ◽

Maize Inbred Lines

Fusarium ear rot of maize, caused by Fusarium verticillioides, is an important disease affecting maize production worldwide. Apart from reducing yield and grain quality, F. verticillioides produces fumonisins which have been associated with mycotoxicoses of animals and humans. Currently, no maize breeding lines are known with resistance to F. verticillioides in South Africa. The objective of this study, therefore, was to evaluate 24 genetically diverse maize inbred lines as potential sources of resistance to Fusarium ear rot and fumonisin accumulation in field trials at Potchefstroom and Vaalharts in South Africa. After artificial silk channel inoculation with F. verticillioides, Fusarium ear rot development was determined at harvest and fumonisins B1, B2, and B3 quantified. A significant inbred line by location effect was observed for Fusarium ear rot severity (P ≤ 0.001), although certain lines proved to be consistently resistant across both locations. The individual inbred lines also differed considerably in fumonisin accumulation between Potchefstroom and Vaalharts, with differentiation between susceptible and potentially resistant inbred lines only being possible at Vaalharts. A greenhouse inoculation trial was then also performed on a subset of potentially resistant and highly susceptible lines. The inbred lines CML 390, CML 444, CML 182, VO 617Y-2, and RO 549 W consistently showed a low Fusarium ear rot (<5%) incidence at both Potchefstroom and Vaalharts and in the greenhouse. Two of these inbred lines, CML 390 and CML 444, accumulated fumonisin levels <5 mg kg–1. These lines could potentially act as sources of resistance for use within a maize breeding program.

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Multi-environment Evaluation of Maize Inbred Lines for Resistance to Fusarium Ear Rot and Fumonisins

Plant Disease ◽

10.1094/pdis-11-15-1360-re ◽

2016 ◽

Vol 100 (10) ◽

pp. 2134-2144 ◽

Cited By ~ 18

Author(s):

L. J. Rose ◽

M. Mouton ◽

I. Beukes ◽

B. C. Flett ◽

C. van der Vyver ◽

...

Keyword(s):

Fusarium Verticillioides ◽

Inbred Lines ◽

Fungal Colonization ◽

Fusarium Ear Rot ◽

Ear Rot ◽

Sources Of Resistance ◽

Resistance Response ◽

Maize Inbred Lines ◽

Target Dna ◽

Local Breeding

Fusarium verticillioides causes Fusarium ear rot (FER) of maize and produces fumonisins, which affects grain quality. Host-plant resistance can reduce both FER and fumonisins in maize. In this study, 18 maize inbred lines were evaluated for resistance to F. verticillioides and fumonisin accumulation at five localities in South Africa. Additive main effects and multiplicative interaction analyses revealed significant environment × genotype interactions, with inbred lines CML 390, US 2540W, RO 424W, and VO 617y-2 consistently exhibiting low FER severity (≤5.4%), fungal target DNA (≤0.1 ng μl−1), and fumonisin levels (≤5.6 ppm). Genotype main effect and genotype × environment biplots showed that inbred lines CML 390, US 2540W, and RO 424W were most resistant to FER, fungal colonization, and fumonisin accumulation, respectively, while inbred line RO 424W was most stable in its resistance response over environments. These inbred lines also demonstrated broad adaptability by consistently exhibiting resistance to FER, fungal colonization, and fumonisins across localities. The identified lines could serve as valuable sources of resistance against F. verticillioides and its fumonisins in local breeding programs.

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Novel Sources of Resistance to Fusarium Stalk Rot of Maize in Tropical Africa

Plant Disease ◽

10.1094/pdis-92-5-0772 ◽

2008 ◽

Vol 92 (5) ◽

pp. 772-780 ◽

Cited By ~ 12

Author(s):

C. G. Afolabi ◽

P. S. Ojiambo ◽

E. J. A. Ekpo ◽

A. Menkir ◽

R. Bandyopadhyay

Keyword(s):

Disease Severity ◽

Natural Infection ◽

Fusarium Verticillioides ◽

Field Trials ◽

Inbred Lines ◽

Disease Assessment ◽

International Institute ◽

Sources Of Resistance ◽

Stalk Rot ◽

Effective Strategies

Fusarium stalk rot is one of the most widespread and destructive diseases of maize, and deployment of resistant genotypes is one of the most effective strategies for controlling the disease. Fifty inbred lines and four checks from the breeding program of the International Institute of Tropical Agriculture were evaluated in field trials at Ikenne and Ibadan, Nigeria in 2003 and 2004 to identify new sources of resistance to stalk rot caused by Fusarium verticillioides. Evaluations were conducted under artificial inoculation and natural infection at Ibadan and Ikenne, respectively. Disease severity was recorded using a severity scale (SS) and direct estimation of stalk discoloration (SD). The two methods of disease assessment were compared and combined to classify genotypes into resistance groups using results from rank-sum analysis. In 2003, disease severity ranged from SS = 1 to 5 and SD = 1.3 to 33.8% at both locations. Both SS and SD were significantly (P < 0.01) higher in 2003 than in 2004 at the two locations. In both years, inbred lines significantly differed in SS (P < 0.02) and SD (P < 0.04) at Ibadan. Similarly, inbred lines significantly differed in SS (P < 0.04) and SD (P < 0.04) when genotypes were evaluated at Ikenne. Disease assessments based on SS and SD were significantly correlated (0.68 < r < 0.95, P < 0.01) in both years. Based on the results from rank-sum analysis, inbred lines were separated into highly resistant, resistant, moderately resistant, moderately susceptible, susceptible, and highly susceptible groups. At Ibadan, 6 (11.1%) and 8 (14.8%) were identified as highly resistant and resistant, respectively, whereas 11 (20.4%) were identified as resistant at Ikenne. Inbred lines 02C14609, 02C14643, 02C14654, and 02C14678 were consistently classified as either highly resistant or resistant to stalk rot across locations and years while the check genotypes were classified either as susceptible or moderately susceptible to stalk rot. These four inbred lines identified to have high levels of disease resistance may be used for breeding maize with resistance to Fusarium stalk rot.

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Differences in Ear Rot Resistance and Fusarium verticillioides-Produced Fumonisin Contamination Between Polish Currently and Historically Used Maize Inbred Lines

Frontiers in Microbiology ◽

10.3389/fmicb.2019.00449 ◽

2019 ◽

Vol 10 ◽

Cited By ~ 1

Author(s):

Elżbieta Czembor ◽

Agnieszka Waśkiewicz ◽

Urszula Piechota ◽

Marta Puchta ◽

Jerzy H. Czembor ◽

...

Keyword(s):

Fusarium Verticillioides ◽

Inbred Lines ◽

Ear Rot ◽

Maize Inbred Lines

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Resistance of some Australian inbred maize lines to maize dwarf mosaic disease

Australian Journal of Experimental Agriculture ◽

10.1071/ea9690541 ◽

1969 ◽

Vol 9 (40) ◽

pp. 541 ◽

Cited By ~ 2

Author(s):

PW Grogan ◽

DS Teakle

Keyword(s):

New South ◽

Natural Infection ◽

New South Wales ◽

Inbred Lines ◽

Mosaic Disease ◽

The Other ◽

Maize Inbred Lines ◽

South Wales ◽

Resistant Lines

Seven out of eight maize inbred lines developed at Lawes in Queensland from open-pollinated varieties were resistant to maize dwarf mosaic disease when exposed to natural infection in the field. Five of the seven resistant inbred lines failed to become systemically infected when inoculated with infectious sap in the glasshouse. By contrast, only three out of twenty lines introduced from the U.S.A., and two out of eight lines developed at the Grafton and Glen Innes Breeding Stations in New South Wales, were resistant in the field. All three resistant lines from the U.S.A. were systemically infected when inoculated in the glasshouse, but the two resistant lines from Grafton in New South Wales were not. The resistant Lawes and Grafton maize inbred lines would appear to be better sources of genes conferring resistance to maize dwarf mosaic disease than the other lines tested.

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The association of maize characteristics with resistance to Fusarium verticillioides and fumonisin accumulation in commercial maize cultivars

World Mycotoxin Journal ◽

10.3920/wmj2019.2537 ◽

2020 ◽

Vol 13 (3) ◽

pp. 367-379

Author(s):

S. Links ◽

K. van Zyl ◽

A. Cassiem ◽

B.C. Flett ◽

A. Viljoen ◽

...

Keyword(s):

Gene Expression ◽

Natural Infection ◽

Fusarium Verticillioides ◽

Field Trials ◽

Disease Development ◽

Ear Rot ◽

Phenotypic Data ◽

Maize Cultivars ◽

Physico Chemical ◽

Grain Yield And Quality

Fusarium verticillioides is the primary fungus that causes Fusarium ear rot (FER) of maize. Infection results in reduced grain yield and quality due to moulding and the contamination of grain with toxic compounds namely fumonisins. Resistance to fungal infection and fumonisin accumulation in maize and maize grain is governed at different levels. In this study, the structural, physico-chemical and genetic basis of resistance to F. verticillioides was investigated in two, replicated field trials at Potchefstroom and Vaalharts in South Africa. Phenotypic data (silk length, husk coverage, pericarp thickness hundred-kernel mass and kernel hardness), physico-chemical data (kernel pH, moisture content, total nitrogen and carbon as well as phenolic acid content) and the expression of pathogenesis-related-5 gene (PR5) and peroxidase gene expression was evaluated in 15 commercial cultivars under artificially inoculated and natural infection conditions. The data were correlated to FER severity, fumonisin accumulation and fungal DNA (referred to as infection indicators). Disease development and fumonisin contamination in Vaalharts was significantly more than in Potchefstroom. There were no significant correlations (r=≥0.60) between phenotypic characteristics and infection indicators. Kernel pH was the most important trait associated with disease development and was negatively correlated (between r=-0.58 and r=-0.75) to all infection indicators. PR5 gene expression had significant positive correlations (r=0.69 and r=0.72) with the fungal and fumonisin levels, respectively. This study presents of the first data demonstrating the use of gene expression in identifying FER/fumonisin-resistant plant material and could aid breeders and growers in selecting resistant material more effectively.

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Evaluation of broad spectrum sources of resistance to Fusarium verticillioides and advanced maize breeding lines

World Mycotoxin Journal ◽

10.3920/wmj2010.1206 ◽

2011 ◽

Vol 4 (1) ◽

pp. 43-51 ◽

Cited By ~ 17

Author(s):

A. Lanubile ◽

L. Pasini ◽

M. Lo Pinto ◽

P. Battilani ◽

A. Prandini ◽

...

Keyword(s):

Host Plant ◽

Natural Infection ◽

Fusarium Verticillioides ◽

Inbred Lines ◽

Ear Rot ◽

Preventive Action ◽

Maize Breeding ◽

Sources Of Resistance ◽

Resistant Parent ◽

Breeding Lines

The fungus Fusarium verticillioides is commonly associated with maize production in temperate regions of the world, producing ear rot and grain contamination by fumonisins. Genetic resistance is the best preventive action against fumonisin contamination, although at present no commercial maize hybrids are completely resistant. Several studies of the relationship between Fusarium and other species producing ear rot suggest that these fungal species interact in similar ways with the host plant. Consequently, host plant resistance to one pathogen could be associated with resistance to another. The aim of this study was to introduce sources of resistance to Fusarium spp. into maize inbred lines and to evaluate ear rot severity and fumonisin B1 contamination in advanced breeding lines and hybrids after artificial and natural infection with F. verticillioides. Two inbred lines (CO430 and MP420) with resistance to kernel infection by Fusarium graminearum and Aspergillus flavus, respectively, were crossed and backcrossed to susceptible inbred 1203. The BC1S1 progenies were evaluated for plant morphology and silk date and the selected S1 plants were self-pollinated. The S2 families were evaluated under artificial and natural infection with F. verticillioides. Selected S2 progenies were grown ear-to-row until S5-derived inbreds were developed. The S5 lines were evaluated under artificial and natural infection and used as males to produce single crosses. In both crosses, the mean ear rot of the S5 lines with the lowest ear rot was not significantly different from the resistant parent means. Significant progress was observed in the hybrids regarding ear rot performance: on average, ear rot severity decreased significantly from 23% in check hybrids to 5.3% in CO430-derived hybrids. Our results suggest that inbred lines bred for resistance to A. flavus and F. graminearum ear rot could be used to select advanced breeding lines with increased resistances to F. verticillioides ear rot.

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