Assessment of yield loss due to northern leaf blight in five maize varieties grown in Tanzania

Reactions of supersweet (sh2) sweet corn to northern leaf blight (NLB) and associated yields were evaluated in Belle Glade, Florida and Urbana, Illinois in yield-loss trials, hybrid evaluations, and evaluations of breeding materials. Hybrids differed significantly for NLB in all trials. Severity of NLB ranged from 0 to 66% on 35 sh2 hybrids in yield-loss trials, and from 0 to 60% on 80 sh2 hybrids in hybrid evaluations. NLB ratings ranged from 1 to 9 (approximately 0 to 80% severity) on 375 hybrids and 186 inbred lines in evaluations of breeding materials. Various methods of rating NLB and ratings from multiple dates were highly correlated, with correlation coefficients ranging from 0.76 to 0.98. Yield, measured as weight of ears and number of marketable ears from inoculated plots as a percentage of that from control plots, decreased as disease severity increased. Linear or quadratic regression models explained 31 to 70% of the variation in percent yield as a function of disease severity at harvest. The effects of NLB on yield were limited by NLB-resistance in several hybrids, including CCO 3268, Chieftain, Crisp N Sweet 710A, Day Star, Envy, Forever, GSS 1526, Jupiter, Midship, Prime Plus, Sch 5005, and SummerSweet 7630. Although high levels of partial resistance to NLB were prevalent among 375 new experimental sh2 hybrids and 186 sh2 inbred lines evaluated in 1995, use of the gene HtN may increase in the near future as breeders are incorporating this resistance into new inbreds and hybrids. Breeders and plant pathologists would be wise to continue improving partial resistance to NLB without using the gene HtN in genotypes with adequate levels of partial resistance, because the widespread use of the gene HtN will select for virulent races of Exserohilum turcicum which occur in Florida, or for races with new combinations of virulence.

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Automated Identification of Northern Leaf Blight-Infected Maize Plants from Field Imagery Using Deep Learning

Phytopathology ◽

10.1094/phyto-11-16-0417-r ◽

2017 ◽

Vol 107 (11) ◽

pp. 1426-1432 ◽

Cited By ~ 67

Author(s):

Chad DeChant ◽

Tyr Wiesner-Hanks ◽

Siyuan Chen ◽

Ethan L. Stewart ◽

Jason Yosinski ◽

...

Keyword(s):

Yield Loss ◽

High Reliability ◽

Leaf Blight ◽

Plant Phenotyping ◽

Computational Pipeline ◽

Limited Data ◽

Northern Leaf Blight ◽

Automated Identification ◽

Precision Breeding ◽

Maize Plants

Northern leaf blight (NLB) can cause severe yield loss in maize; however, scouting large areas to accurately diagnose the disease is time consuming and difficult. We demonstrate a system capable of automatically identifying NLB lesions in field-acquired images of maize plants with high reliability. This approach uses a computational pipeline of convolutional neural networks (CNNs) that addresses the challenges of limited data and the myriad irregularities that appear in images of field-grown plants. Several CNNs were trained to classify small regions of images as containing NLB lesions or not; their predictions were combined into separate heat maps, then fed into a final CNN trained to classify the entire image as containing diseased plants or not. The system achieved 96.7% accuracy on test set images not used in training. We suggest that such systems mounted on aerial- or ground-based vehicles can help in automated high-throughput plant phenotyping, precision breeding for disease resistance, and reduced pesticide use through targeted application across a variety of plant and disease categories.

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Use of Disease Assessment Methods in Predicting Yield Loss Due to Northern Leaf Blight of Maize

African Crop Science Journal ◽

10.4314/acsj.v1i2.69907 ◽

2011 ◽

Vol 1 (2) ◽

Cited By ~ 1

Author(s):

E Adipala ◽

PE Lipps ◽

LV Madden

Keyword(s):

Yield Loss ◽

Leaf Blight ◽

Assessment Methods ◽

Disease Assessment ◽

Northern Leaf Blight

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Assessing the Potential of Extra-Early Maturing Landraces for Improving Tolerance to Drought, Heat, and Both Combined Stresses in Maize

Agronomy ◽

10.3390/agronomy10030318 ◽

2020 ◽

Vol 10 (3) ◽

pp. 318 ◽

Cited By ~ 5

Author(s):

Charles Nelimor ◽

Baffour Badu-Apraku ◽

Antonia Yarney Tetteh ◽

Ana Luísa Garcia-Oliveira ◽

Assanvo Simon-Pierre N’guetta

Keyword(s):

Heat Stress ◽

Abiotic Stress ◽

Field Experiments ◽

Yield Loss ◽

Yield Potential ◽

Genetic Base ◽

Maize Varieties ◽

Early Maturing ◽

Maize Landraces ◽

Landrace Accessions

Maize landrace accessions constitute an invaluable gene pool of unexplored alleles that can be harnessed to mitigate the challenges of the narrowing genetic base, declined genetic gains, and reduced resilience to abiotic stress in modern varieties developed from repeated recycling of few superior breeding lines. The objective of this study was to identify extra-early maize landraces that express tolerance to drought and/or heat stress and maintain high grain yield (GY) with other desirable agronomic/morpho-physiological traits. Field experiments were carried out over two years on 66 extra-early maturing maize landraces and six drought and/or heat-tolerant populations under drought stress (DS), heat stress (HS), combined both stresses (DSHS), and non-stress (NS) conditions as a control. Wide variations were observed across the accessions for measured traits under each stress, demonstrating the existence of substantial natural variation for tolerance to the abiotic stresses in the maize accessions. Performance under DS was predictive of yield potential under DSHS, but tolerance to HS was independent of tolerance to DS and DSHS. The accessions displayed greater tolerance to HS (23% yield loss) relative to DS (49% yield loss) and DSHS (yield loss = 58%). Accessions TZm-1162, TZm-1167, TZm-1472, and TZm-1508 showed particularly good adaptation to the three stresses. These landrace accessions should be further explored to identify the genes underlying their high tolerance and they could be exploited in maize breeding as a resource for broadening the genetic base and increasing the abiotic stress resilience of elite maize varieties.

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Targeted discovery of quantitative trait loci for resistance to northern leaf blight and other diseases of maize

Theoretical and Applied Genetics ◽

10.1007/s00122-011-1585-9 ◽

2011 ◽

Vol 123 (2) ◽

pp. 307-326 ◽

Cited By ~ 29

Author(s):

Chia-Lin Chung ◽

Jesse Poland ◽

Kristen Kump ◽

Jacqueline Benson ◽

Joy Longfellow ◽

...

Keyword(s):

Quantitative Trait Loci ◽

Quantitative Trait ◽

Leaf Blight ◽

Northern Leaf Blight ◽

Trait Loci

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Effect of planting density of maize on the progress and spread of northern leaf blight fromExserohilum turcicum infested residue source

European Journal of Plant Pathology ◽

10.1007/bf01876091 ◽

1995 ◽

Vol 101 (1) ◽

pp. 25-33 ◽

Cited By ~ 8

Author(s):

E. Adipala ◽

J. P. Takan ◽

M. W. Ogenga-Latigo

Keyword(s):

Leaf Blight ◽

Planting Density ◽

Northern Leaf Blight

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Use of a Maize Advanced Intercross Line for Mapping of QTL for Northern Leaf Blight Resistance and Multiple Disease Resistance

Crop Science ◽

10.2135/cropsci2009.02.0066 ◽

2010 ◽

Vol 50 (2) ◽

pp. 458-466 ◽

Cited By ~ 34

Author(s):

Peter J. Balint-Kurti ◽

Junyun Yang ◽

George Van Esbroeck ◽

Janelle Jung ◽

Margaret E. Smith

Keyword(s):

Disease Resistance ◽

Leaf Blight ◽

Blight Resistance ◽

Northern Leaf Blight ◽

Advanced Intercross Line ◽

Multiple Disease Resistance

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Trichometasphaeria turcica. [Descriptions of Fungi and Bacteria].

IMI Descriptions of Fungi and Bacteria ◽

10.1079/dfb/20056400304 ◽

1971 ◽

Author(s):

M. B. Ellis

Keyword(s):

Zea Mays ◽

Saudi Arabia ◽

Geographical Distribution ◽

Leaf Blight ◽

Diurnal Periodicity ◽

Northern Leaf Blight ◽

Setosphaeria Turcica ◽

Seedling Infection

Abstract A description is provided for Trichometasphaeria turcica[Setosphaeria turcica]. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: On Zea mays, Sorghum spp., Euchlaena mexicana and other Gramineae (RAM 41: 40). DISEASE: Northern leaf blight of maize and sorghum forming larger and fewer lesions than Cochlioholus heterostrophus (CMI Descript. 301), mostly on the leaves. They begin as small, dark, water-soaked areas, becoming irregular or elliptical, sometimes linear, brown then straw coloured or greyish, with red-purple or tan borders, often 4 × 10 cm or larger, coalescing and leading to death of leaves. Tassel infection on maize is less conspicuous, ear and crown rots and seedling infection occur (16: 450; 34: 716). GEOGRAPHICAL DISTRIBUTION: Widespread (CMI Map 257, ed. 3, 1968). Additional records not yet mapped are: Australia (NT), Cameroon, Ecuador, Fiji, Haiti, Indonesia, Iraq, Lebanon, Pakistan (E.) and Saudi Arabia. TRANSMISSION: Air-dispersed, probably violently discharged conidia and showing a diurnal periodicity with a forenoon max. (45, 795; 46, 114). The fungus occurs in seed and survives in host debris (15: 289; 19: 602).

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