Advances in understanding the epidemiology, molecular biology and control of net blotch and the net blotch barley interaction

2021 ◽  
pp. 477-524
Author(s):  
Anke Martin ◽  
◽  
Barsha Poudel ◽  
Buddhika Amarasinghe Dahanayaka ◽  
Mark S. McLean ◽  
...  

Net blotches are the most widely distributed foliar diseases of barley worldwide, causing significant losses in grain yield. They occur as net form net blotch, caused by Pyrenophora teres f. teres and spot form net blotch caused by P. teres f. maculata. Both sexual and asexual reproduction play a role in the P. teres disease cycles leading to changes in genetic variation of populations. Breeding programs have to keep pace with pathogenic changes and ensure different sources of resistance are present in current barley cultivars. Knowledge of the genetic architecture and genes involved in virulence is thus vital to increase the durability of net blotch resistance in barley cultivars. This chapter explores the molecular biology, life-cycle and epidemiology of the net blotch fungi and discusses the key challenges we are facing in managing the net blotches using both fungicide resistance and breeding strategies to achieve durable disease resistance in barley.

1977 ◽  
Vol 57 (2) ◽  
pp. 389-395 ◽  
Author(s):  
A. TEKAUZ ◽  
K. W. BUCHANNON

The distribution in western Canada of three biotypes of Pyrenophora teres, the cause of net blotch of barley, was determined. Two of these produced typical net blotch symptoms but differed in virulence and were found throughout the prairies in 1974. The third, which produces spot-like symptoms, was found only in Manitoba and comprised half the total isolates. The incidence of net blotch was higher in fields of two-rowed than in six-rowed barley. Resistance to the three biotypes of P. teres was found in several barley lines when symptom expression and rate of conidial development on infected host tissue were compared. CI 9214 was superior to CI 5791, the resistance source used in some barley breeding programs.


2015 ◽  
Vol 105 (4) ◽  
pp. 509-517 ◽  
Author(s):  
A. Neupane ◽  
P. Tamang ◽  
R. S. Brueggeman ◽  
T. L. Friesen

Spot form net blotch (SFNB) caused by Pyrenophora teres f. maculata is a major foliar disease of barley (Hordeum vulgare) worldwide. SFNB epidemics have recently been observed in major barley producing countries, suggesting that the local barley cultivars are not resistant and that virulence of the local pathogen populations may have changed. Here we attempt to identify sources of resistance effective against four diverse isolates of P. teres f. maculata collected from around the world. A total of 2,062 world barley core collection accessions were phenotyped using isolates of the pathogen collected in the United States (FGO), Australia (SG1), New Zealand (NZKF2), and Denmark (DEN 2.6). Isolate-specific susceptibility was identified in several of the barley accessions tested, indicating variability in both pathogen virulence and host resistance/susceptibility. Collectively, only 15 barley accessions were resistant across all isolates tested. These resistant accessions will be used to generate mapping populations and for germplasm development. Future research will involve the characterization of host resistance, pathogen virulence, and the host−pathogen interaction associated with SFNB of barley.


2018 ◽  
Vol 17 (1) ◽  
pp. 1-24 ◽  
Author(s):  
Shakhawat Chowdhury

Abstract Desalinated seawater is the major source of drinking water in many countries. During desalination, several activities including pretreatment, desalination, stabilization, mixing, storage and distribution are performed. Few disinfectants are used during these activities to control the biofouling agents and microbiological regrowth. The reactions between the disinfectants and natural organic matter (NOM), bromide and iodide form disinfection by-products (DBPs) in product water. The product water is stabilized and mixed with treated freshwater (e.g., groundwater) to meet the domestic water demands. The DBPs in desalinated and blend water are an issue due to their possible cancer and non-cancer risks to humans. In this paper, formation and distribution of DBPs in different steps of desalination and water distribution systems prior to reaching the consumer tap were reviewed. The variability of DBPs among different sources and desalination processes was explained. The toxicities of DBPs were compared and the strategies to control DBPs in desalinated water were proposed. Several research directions were identified to achieve comprehensive control on DBPs in desalinated water, which are likely to protect humans from the adverse consequences of DBPs.


Euphytica ◽  
2021 ◽  
Vol 217 (8) ◽  
Author(s):  
Oula Maafi ◽  
Pedro Revilla ◽  
Lorena Álvarez-Iglesias ◽  
Rosa Ana Malvar ◽  
Abderahmane Djemel

AbstractDrought is the main stress for agriculture, and maize (Zea mays L.) germplasm from the Sahara has been identified as potential source of drought tolerance; however, information about adaptation of semitropical maize germplasm from the Sahara to temperate areas has not been reported. Our objective was assessing the adaptation of maize germplasm from Saharan oases as sources of drought tolerance for improving yield and biomass production under drought conditions in temperate environments. A collection of maize populations from Saharan oases was evaluated under drought and control conditions in Spain and Algeria. Algerian populations were significantly different under drought for most traits, and the significant genotype × environment interactions indicated that drought tolerance is genotype-dependent, but tolerance differences among genotypes change across environments. Based on yield, the Algerian maize populations PI527474, PI527478, PI527472, PI527467, PI527470, and PI527473 would be appropriate sources of drought tolerance for temperate environments. Concerning biomass production, the most interesting populations were PI527467, PI542685, PI527478, and PI527472. These Saharan populations could provide favorable alleles for drought tolerance for temperate breeding programs, and could also be used for studying mechanisms and genetic regulation of drought tolerance.


Plants ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 1228
Author(s):  
Carla Colque-Little ◽  
Daniel Buchvaldt Amby ◽  
Christian Andreasen

The journey of the Andean crop quinoa (Chenopodium quinoa Willd.) to unfamiliar environments and the combination of higher temperatures, sudden changes in weather, intense precipitation, and reduced water in the soil has increased the risk of observing new and emerging diseases associated with this crop. Several diseases of quinoa have been reported in the last decade. These include Ascochyta caulina, Cercospora cf. chenopodii, Colletotrichum nigrum, C. truncatum, and Pseudomonas syringae. The taxonomy of other diseases remains unclear or is characterized primarily at the genus level. Symptoms, microscopy, and pathogenicity, supported by molecular tools, constitute accurate plant disease diagnostics in the 21st century. Scientists and farmers will benefit from an update on the phytopathological research regarding a crop that has been neglected for many years. This review aims to compile the existing information and make accurate associations between specific symptoms and causal agents of disease. In addition, we place an emphasis on downy mildew and its phenotyping, as it continues to be the most economically important and studied disease affecting quinoa worldwide. The information herein will allow for the appropriate execution of breeding programs and control measures.


2021 ◽  
pp. 105678
Author(s):  
Alezania Silva Pereira ◽  
Uilson Vanderlei Lopes ◽  
José Luís Pires ◽  
Mariana Araujo Barreto ◽  
Lindolfo Pereira dos Santos ◽  
...  

1969 ◽  
Vol 11 (3) ◽  
pp. 587-591 ◽  
Author(s):  
T. N. Khan

Variability in the host-reaction of barley to infection by Drechslera teres was examined in the parents and progeny of selected crosses under different environmental conditions of testing.The Ethiopian variety C.I. 5791 exhibits a consistently high level of resistance under a range of environmental conditions, which is in contrast to the Manchurian variety C.I. 2330. The sensitivity of the genes for resistance possessed by these varieties to environmental modifications is considered to depend upon their respective genetic backgrounds. Furthermore, variability of host reaction in the progeny of these resistant varieties was shown to be influenced by the genetic background of the susceptible parent used.The implications of these findings in the conduct and interpretation of genetic studies and in backcross breeding programs is discussed.


Toxins ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 92
Author(s):  
Dipendra Kumar Mahato ◽  
Sheetal Devi ◽  
Shikha Pandhi ◽  
Bharti Sharma ◽  
Kamlesh Kumar Maurya ◽  
...  

Mycotoxins represent an assorted range of secondary fungal metabolites that extensively occur in numerous food and feed ingredients at any stage during pre- and post-harvest conditions. Zearalenone (ZEN), a mycotoxin categorized as a xenoestrogen poses structural similarity with natural estrogens that enables its binding to the estrogen receptors leading to hormonal misbalance and numerous reproductive diseases. ZEN is mainly found in crops belonging to temperate regions, primarily in maize and other cereal crops that form an important part of various food and feed. Because of the significant adverse effects of ZEN on both human and animal, there is an alarming need for effective detection, mitigation, and management strategies to assure food and feed safety and security. The present review tends to provide an updated overview of the different sources, occurrence and biosynthetic mechanisms of ZEN in various food and feed. It also provides insight to its harmful effects on human health and agriculture along with its effective detection, management, and control strategies.


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