Identification and characterization of maize lines resistant to leaf diseases

Among the maize leaf diseases, white leaf spot, northern leaf blight, gray leaf spot, and southern rust are recognized not only by the potential for grain yield reduction but also by the widespread occurrence in the producing regions of Brazil and the world. The aim of this study was to characterize common maize lines for resistance to white leaf spot, northern leaf blight, gray leaf spot, and southern rust and suggest crosses based on the genetic diversity detected in SNP markers. The experiment was conducted in a randomized block design with three replications in order to characterize 72 maize lines. Genotypic values were predicted using the REML/BLUP procedure. These 72 lines were genotyped with SNP markers using the 650K platform (Affymetrix®) for the assessment of the genetic diversity. Genetic diversity was quantified using the Tocher and UPGMA methods. The existence of genetic variability for disease resistance was detected among maize lines, which made possible to classify them into three large groups (I, II, and III). The maize lines CD 49 and CD50 showed a good performance and can be considered sources of resistance to diseases. Therefore, their use as gene donors in maize breeding programs is recommended. Considering the information of genetic distance together with high heritability for leaf diseases, backcrossing of parent genotypes with different resistance levels, such as those of the lines CD49 x CD69 and CD50 x CD16, may result in new gene combinations, as they are divergent and meet good performances.

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Severity of leaf diseases in maize inbred lines with different kernel hardness in two sowing seasons

Semina Ciências Agrárias ◽

10.5433/1679-0359.2018v39n1p29 ◽

2018 ◽

Vol 39 (1) ◽

pp. 29

Author(s):

Cecília Aparecida Spada ◽

Marcos Ventura Faria ◽

Marcelo Cruz Mendes ◽

Welton Luiz Zaluski ◽

Emanuel Gava ◽

...

Keyword(s):

Leaf Spot ◽

Inbred Lines ◽

Gray Leaf Spot ◽

Leaf Blight ◽

Kernel Hardness ◽

Northern Leaf Blight ◽

Maize Inbred Lines ◽

Progress Curve ◽

White Leaf ◽

Cercospora Zeae Maydis

Resistance of maize inbred lines to major leaf diseases should be characterized for the development of new hybrids in breeding programs. Thus, this study aimed to assess the severity of leaf diseases in maize inbredlines with different kernel hardnessand two sowingseasons. We assessed four inbred lines and one check hybrid with dent kernels and four inbred lines and a check hybrid with flint kernels. Treatments were conducted in two sowing seasons, one in October, and another in December 2013. The symptoms of gray leaf spot (Cercospora zeae-maydis), northern leaf blight (Exserohilum turcicum), and white leaf spot (a complex of Phaeosphaeria maydis and Pantoea ananatis) were assessed every 10 days from flowering. The area under the disease progress curve was also calculated. Severity level of the diseases was higher in inbred lines when compared to the check hybrds (AG8041 PRO and P30R50YH), regardless of kernel hardness. Dent-kernel inbred lines showed a higher severity of northern leaf blight symptoms when compared to flint-kernelones. It is worth mentioning that disease severity increased as sowing was delayed.

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Prevalence, Incidence, and Severity of Sorghum Diseases in Western Kenya

Plant Disease ◽

10.1094/pdis.2002.86.1.65 ◽

2002 ◽

Vol 86 (1) ◽

pp. 65-70 ◽

Cited By ~ 27

Author(s):

H. K. Ngugi ◽

S. B. King ◽

G. O. Abayo ◽

Y. V. R. Reddy

Keyword(s):

Disease Severity ◽

Leaf Spot ◽

Gaussian Model ◽

Gray Leaf Spot ◽

Distribution Functions ◽

Leaf Blight ◽

Yield Reduction ◽

Production Environment ◽

Head Smut ◽

Western Kenya

To assess the prevalence and severity of sorghum diseases in western Kenya, a 2-year survey was conducted (July 1995 and 1996), in 91 and 109 farmers' fields, respectively. Fields were generally <0.5 ha and production environment ranged from warm-humid to warm-semi-arid. Fourteen foliar and six panicle diseases were observed, with limited variation in disease prevalence and severity between the 2 years. The most common foliar diseases observed were (in decreasing order of prevalence) oval leaf spot (Ramulispora sorghicola), rust (Puccinia purpurea), ladder leaf spot (Cercospora fusimaculans), zonate leaf spot (Gloeocercospora sorghi), gray leaf spot (Cercospora sorghi), leaf blight (Exserohilum turcicum), and anthracnose (Colletotrichum sublineolum); with prevalence ranging from 95 to 97% of fields for oval leaf spot, and 44 to 65% of fields for anthracnose. Head smut (Sporisorium reilianum), was observed in 73 to 75% of fields, covered kernel smut (S. sorghi) 42 to 43% of fields, and loose smut (S. cruenta) 14 to 24% of fields. Head smut incidence was >25% in 3% of fields surveyed. Grain yield reduction from smut diseases alone was estimated to be 5%. Out of eight probability distribution functions compared, the double Gaussian model best described the frequency of disease severity levels for most diseases. Based on the best-fitting model, the proportion of fields with disease severity level thought to cause yield loss (severity rating >5 on a 1 to 9 scale, where 1 = no disease) was calculated as 26.6% for oval leaf spot, 15.3% for rust, 14.8% for anthracnose, 4.8% for ladder leaf spot, and 1.5% for leaf blight. The production environment influenced the prevalence of disease severity. Severe anthracnose, leaf blight, and ladder leaf spot were confined to fields in the humid LM1 and LM2 agro-ecological zones, rust was ubiquitous, and severe gray leaf spot was more prevalent in the dryer LM4 zone.

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Adaptability and stability of corn inbred lines regarding resistance to gray leaf spot and northern leaf blight

Cropp Breeding and Applied Biotechnology ◽

10.1590/1984-70332018v18n2a21 ◽

2018 ◽

Vol 18 (2) ◽

pp. 148-154 ◽

Cited By ~ 2

Author(s):

Belisa Cristina Saito ◽

Leonardo Queiroz Silva ◽

João Antonio da Costa Andrade ◽

Major M Goodman

Keyword(s):

Leaf Spot ◽

Inbred Lines ◽

Gray Leaf Spot ◽

Leaf Blight ◽

Northern Leaf Blight ◽

Corn Inbred

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Septoria cannabis. [Descriptions of Fungi and Bacteria].

IMI Descriptions of Fungi and Bacteria ◽

10.1079/dfb/20056400668 ◽

1980 ◽

Author(s):

E. Punithalingam

Keyword(s):

North America ◽

Geographical Distribution ◽

Leaf Spot ◽

Crop Residues ◽

New Records ◽

Cannabis Sativa ◽

Leaf Blight ◽

White Leaf ◽

Rain Splash

Abstract A description is provided for Septoria cannabis. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOST: Cannabis sativa (hemp). DISEASE: White leaf spot or leaf blight of hemp. Symptoms usually appear on basal leaves as round or ellipsoidal to polygonal, whitish or ochraceous yellow lesions with a conspicuous dark brown border. Affected leaves become curled and withered up towards the edges and fall prematurely leaving much of the lower part of the stem defoliated (15, 97, 805). GEOGRAPHICAL DISTRIBUTION: Asia, Europe and North America (CMI Map No. 477, ed. 1, 1971). New records not mapped are: Asia (Kashmir, Pakistan). TRANSMISSION: Detailed studies have not been reported but conidia are presumed to be disseminated by rain-splash and wind blown water. The fungus could also be carried over in crop residues.

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Identification of Sources of Resistance to Gray leaf spot in Stenotaphrum germplasm

Crop Science ◽

10.1002/csc2.20371 ◽

2020 ◽

Author(s):

Esdras M. Carbajal ◽

Bangya Ma ◽

M. Carolina Zuleta ◽

W. Casey Reynolds ◽

Consuelo Arellano ◽

...

Keyword(s):

Leaf Spot ◽

Gray Leaf Spot ◽

Sources Of Resistance

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Sources of Resistance to Gray Leaf Spot of Corn

Plant Disease ◽

10.1094/pd-78-1153 ◽

1994 ◽

Vol 78 (12) ◽

pp. 1153 ◽

Cited By ~ 13

Author(s):

S. T. COATES

Keyword(s):

Leaf Spot ◽

Gray Leaf Spot ◽

Sources Of Resistance

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High-density Mapping for Gray Leaf Spot Resistance using Two Related Tropical Maize RIL Populations

10.21203/rs.3.rs-179335/v1 ◽

2021 ◽

Author(s):

Long Chen ◽

Li Liu ◽

Ziwei Li ◽

Yudong Zhang ◽

Manjit S Kang ◽

...

Keyword(s):

Leaf Spot ◽

Large Scale ◽

Gene Annotation ◽

Snp Markers ◽

Gray Leaf Spot ◽

High Density ◽

Genetic Maps ◽

Phenotypic Variance ◽

Maize Breeding ◽

Density Mapping

Abstract The identification of QTL/genes to resist gray leaf spot (GLS) caused by Cercospora zeae-maydis or Cercospora Zeina plays an urgent role in improving GLS resistance in maize breeding practice. In our study, two groups of recombinant inbred line (RIL) populations derived from CML373×Ye107 (176 RILs) and Chang7-2×Ye107 (190 RILs) were generated and subjected to genotyping-by-sequencing (GBS). GBS technology was used for large-scale single nucleotide polymorphism (SNP) discovery and simultaneous genotyping of all F7 lines from two related RIL populations in order to identify quantitative trait loci (QTL) associated with GLS resistance under natural conditions of disease occurrence. A total of 1929222287 reads in CML373×Ye107 (RIL-YCML) and 2585728312 reads in Chang7-2×Ye107 (RIL-YChang), with an average of 10961490 (RIL-YCML) and 13609096 (RIL-YChang) reads per individual, were got, which was roughly equal to 0.70-fold and 0.87-fold coverage of the maize B73 RefGen_V4 genome for each F7 individual, respectively. 6418 and 5139 SNP markers were extracted to construct two high-density genetic maps. Comparative analysis using these physically mapped marker loci demonstrated a satisfactory colinear relationship with the reference genome. Eleven GLS-resistant QTL have been detected. The individual QTL accounted for 2.05-24.00% of the phenotypic variance explained (PVE). The new consensus QTL (qYCM-DS3-3/ qYCM-LT3-1/ qYCM-LT3-2) with the largest effect was located in chromosome bin 3.05, with an interval of 2.7 Mb, representing 13.08 to 24.00% of the PVE. Further gene annotation indicated that there were four candidate genes (GRMZM2G032384, GRMZM2G041415, GRMZM2G041544, and GRMZM2G035992) for qYCM-LT3-1, which may be related to GLS resistance.

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Genetic control of resistance to gray leaf spot of maize in tropical germplasm

Cropp Breeding and Applied Biotechnology ◽

10.1590/s1984-70332012000200008 ◽

2012 ◽

Vol 12 (2) ◽

pp. 145-150 ◽

Cited By ~ 2

Author(s):

André Humberto de Brito ◽

Livia Maria Chamma Davide ◽

Renzo Garcia Von Pinho ◽

Rafael Pelloso de Carvalho ◽

Matheus Costa dos Reis

Keyword(s):

Genetic Control ◽

Leaf Spot ◽

Genetic Model ◽

Block Design ◽

Gray Leaf Spot ◽

Cercospora Leaf Spot ◽

Gene Effects ◽

Randomized Block Design ◽

Tropical Germplasm ◽

Plant Level

The main goal of this study was to assess the nature and magnitude of gene effects for resistance to Cercospora leaf spot. A randomized block design with three replications was used. The data were obtained at the plant level by assessing the disease severity. The data were analyzed per experiment, using the average data per plot. A dominant-additive genetic model without epistasis was considered, with estimation of the components of means and variance. The genetic control of resistance to gray leaf spot is polygenic with predominance of the additive effects. Dominance was observed in a few small-effect loci and high heritability values.

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Benefits of maize resistance breeding and chemical control against northern leaf blight in smallholder farms in South Africa

South African Journal of Science ◽

10.17159/sajs.2020/8286 ◽

2020 ◽

Vol 116 (11/12) ◽

Author(s):

Dave K. Berger ◽

Tumisang Mokgobu ◽

Katrien de Ridder ◽

Nanette Christie ◽

Theresa A.S. Aveling

Keyword(s):

South Africa ◽

Disease Resistance ◽

Leaf Spot ◽

Smallholder Farmers ◽

Resistance Breeding ◽

Leaf Blight ◽

Northern Leaf Blight ◽

Maize Hybrids ◽

Kwazulu Natal ◽

Disease Resistance Breeding

Maize underpins food security in South Africa. An annual production of more than 10 million tons is a combination of the output of large-scale commercial farms plus an estimated 250 000 ha cultivated by smallholder farmers. Maize leaves are a rich source of nutrients for fungal pathogens. Farmers must limit leaf blighting by fungi to prevent sugars captured by photosynthesis being ‘stolen’ instead of filling the grain. This study aimed to fill the knowledge gap on the prevalence and impact of fungal foliar diseases in local smallholder maize fields. A survey with 1124 plant observations from diverse maize hybrids was conducted over three seasons from 2015 to 2017 in five farming communities in KwaZulu-Natal Province (Hlanganani, Ntabamhlophe, KwaNxamalala) and Eastern Cape Province (Bizana, Tabankulu). Northern leaf blight (NLB), common rust, Phaeosphaeria leaf spot, and grey leaf spot had overall disease incidences of 75%, 77%, 68% and 56%, respectively, indicating high disease pressure in smallholder farming environments. NLB had the highest disease severity (LSD test, p<0.05). A yield trial focused on NLB in KwaZulu-Natal showed that this disease reduced yields in the three most susceptible maize hybrids by 36%, 71% and 72%, respectively. Eighteen other hybrids in this trial did not show significant yield reductions due to NLB, which illustrates the progress made by local maize breeders in disease resistance breeding. This work highlights the risk to smallholder farmers of planting disease-susceptible varieties, and makes recommendations on how to exploit the advances of hybrid maize disease resistance breeding to develop farmer-preferred varieties for smallholder production.

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Increased Severity of Foliar Diseases of Sweet Corn Infected with Maize Dwarf Mosaic and Sugarcane Mosaic Viruses

Plant Disease ◽

10.1094/pdis-94-9-1093 ◽

2010 ◽

Vol 94 (9) ◽

pp. 1093-1099 ◽

Cited By ~ 11

Author(s):

M. D. Meyer ◽

J. K. Pataky

Keyword(s):

Virus Infection ◽

Mosaic Virus ◽

Leaf Spot ◽

Sweet Corn ◽

Viral Disease ◽

Gray Leaf Spot ◽

Leaf Blight ◽

Maize Dwarf Mosaic Virus ◽

Foliar Diseases ◽

Corn Leaf Blight

Maize dwarf mosaic (MDM), caused by Maize dwarf mosaic virus (MDMV) and Sugarcane mosaic virus (SCMV), is an economically important viral disease of sweet corn (Zea mays). MDM is known to increase the severity of fungal root rots and southern corn leaf blight (SCLB). The effect of infection with MDMV-A and SCMV on eight foliar diseases was evaluated on 32 sweet corn hybrids (27 MDM-susceptible hybrids and five MDM-resistant hybrids) in 2007, 2008, and 2009. Virus infection substantially increased the severity of five diseases, including: SCLB, northern corn leaf spot (NCLS), gray leaf spot (GLS), Diplodia leaf streak (DLS), and eyespot. Among MDM-susceptible hybrids, mean severity of SCLB, NCLS, GLS, DLS, and eyespot on virus-infected plants was typically double that of plants that were asymptomatic of viral infection. Three diseases were not substantially increased by MDM, including: common rust, northern corn leaf blight (NCLB), and Stewart's wilt. Virus infection appeared to affect the severity of diseases caused by necrotrophic foliar fungi that colonize mesophyll tissue. MDM did not appear to substantially affect the severity of diseases caused by pathogens that form haustoria or invade the vascular system. The extent to which SCLB severity is increased by MDM in terms of changes in level of host resistance also was determined. For MDM-susceptible hybrids, reactions to SCLB ranged from resistant to moderately susceptible in MDM-free treatments, but each of these hybrids was classified as moderately susceptible to susceptible when infected with MDMV-A and/or SCMV. The results of this experiment demonstrate the importance of breeding for MDM resistance, not only to control this important viral disease of sweet corn, but also to lower the potential for detrimental effects from several other foliar diseases that often are of minor importance on sweet corn in the absence of MDM.

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