scholarly journals Importance of the Secondary Genepool in Barley Genetics and Breeding II. Disease Resistance, Agronomic Performance and Quality

2011 ◽  
Vol 40 (No. 3) ◽  
pp. 79-85 ◽  
Author(s):  
R. Pickering ◽  
E. Niks R ◽  
A. Johnston P ◽  
C. Butler R
Keyword(s):  
Disease Resistance ◽  
Leaf Rust ◽  
Partial Resistance ◽  
Disease Development ◽  
Agronomic Performance ◽  
Yield And Quality ◽  
Complete Resistance ◽  
High Level ◽  
Yield Trials ◽  
Breeding Techniques

In this second paper on the use of secondary genepools in barley improvement, we describe the characterisation of leaf rust resistant recombinant lines (RLs) derived from Hordeum vulgare × H. bulbosum crosses. Twelve RLs were inoculated with leaf rust and the early stages of disease development were observed. Several RLs showed complete resistance to the pathogen, but others had a high level of partial resistance, which may be durable. Some of these RLs and others were tested in yield trials to determine the effects of introgressed chromatin from H. bulbosum on yield and quality. We conclude that there are no major adverse effects that cannot be overcome through normal breeding techniques.  

scholarly journals Managing the Race Structure of Phytophthora parasitica var. nicotianae with Cultivar Rotation

Plant Disease ◽  
2005 ◽  
Vol 89 (12) ◽  
pp. 1285-1294 ◽  
Author(s):  
M. J. Sullivan ◽  
T. A. Melton ◽  
H. D. Shew
Keyword(s):  
Partial Resistance ◽  
Disease Incidence ◽  
Single Gene ◽  
Growing Season ◽  
Phytophthora Parasitica ◽  
Black Shank ◽  
Complete Resistance ◽  
Race 1 ◽  
High Level ◽  
Different Levels

Deployment of tobacco cultivars with single-gene, complete resistance to race 0 of the tobacco black shank pathogen, Phytophthora parasitica var. nicotianae, has resulted in a rapid increase in the occurrence of race 1 of the pathogen in North Carolina. Cultivar-rotation studies were conducted in three fields to assess how different levels and types of resistance affected the race structure and population dynamics of the pathogen when deployed in fields initially containing single or mixed races of the pathogen. In a field with both races present, a high level of partial resistance in cv. K 346 was most effective in reducing disease and decreasing the proportion of race 1 in the pathogen population. The deployment of complete resistance in cv. NC 71 resulted in intermediate levels of disease control and race 1 became the predominate race. The cv. K 326, with a low level of partial resistance, had the highest levels of disease, and race 0 was the dominant race recovered. In a field where no race 1 was detected initially, disease incidence was high with the use of partial resistance. Complete resistance was very effective in suppressing disease, but race 1 was recovered after only one growing season. By the end of the third growing season, race 1 was recovered from most treatments where single-gene resistance was deployed. A high level of partial resistance was most effective in suppressing disease in a field where race 1 initially was the predominant race. A rotation between cultivars with single-gene resistance and cultivars with a high level of partial resistance should provide the most effective approach to black shank management. This rotation will reduce disease incidence and minimize race shifts in the pathogen and, over time, should prolong the usefulness of the Ph gene for black shank control in commercial production of tobacco.

scholarly journals Partial Resistance to Melampsora larici-populina Leaf Rust in Hybrid Poplars: Genetic Variability in Inoculated Excised Leaf Disk Bioassay and Relationship with Complete Resistance

2003 ◽  
Vol 93 (4) ◽  
pp. 421-427 ◽  
Author(s):  
A. Dowkiw ◽  
C. Husson ◽  
P. Frey ◽  
J. Pinon ◽  
C. Bastien
Keyword(s):  
Leaf Rust ◽  
Partial Resistance ◽  
Populus Deltoides ◽  
Major Gene ◽  
Bimodal Distribution ◽  
Leaf Disk ◽  
Additional Information ◽  
Progress Curve ◽  
Residual Variation ◽  
Complete Resistance

Inoculated excised leaf disk technique allows decomposition of poplar partial resistance to Melampsora larici-populina leaf rust into key epidemiological components such as latent period (LP), uredinia number (UN), uredinia size (US), and spore production (SP) for a given M. larici-populina strain under controlled environmental conditions. Three hundred thirty-six genotypes from an interspecific Populus deltoides × P. trichocarpa F1 progeny segregating for complete resistance to M. larici-populina strain 93ID6 were inoculated with M. larici-populina strain 93CV1. This strain was able to infect the whole family, except few probable recombinants. LP, final UN, and final US after one infectious cycle proved to be relevant complementary descriptors of partial resistance. Area under the disease progress curve and other parameters of uredinia appearance dynamics did not yield additional information. Indirect assessment of SP by US scoring was reliable and easy to access compared with direct spore counting. UN was the only trait for which a doubling of the inoculum pressure level had a significant effect, leading to greater differentiation between genotypes. Consistent with previous studies is the clear relationship between presence of complete resistance against M. larici-populina strain 93ID6 and higher partial resistance to M. larici-populina strain 93CV1 (32% longer LP, 76% smaller UN, and 34% smaller US). In the subpopulation compatible with 93ID6, bimodal distribution of genotypic means for US suggested implication of a major gene inherited from the P. trichocarpa parent. Residual variation was noted for the three epidemiological components, suggesting that additional genes might condition these quantitative traits.

THE INHERITANCE OF RESISTANCE IN RYE TO Puccinia recondita f. sp. secalis and f. sp. tritici

1984 ◽  
Vol 64 (3) ◽  
pp. 511-519 ◽  
Author(s):  
G. L. C. MUSA ◽  
P. L. DYCK ◽  
D. J. SAMBORSKI
Keyword(s):  
Disease Resistance ◽  
Leaf Rust ◽  
Secale Cereale ◽  
Single Gene ◽  
Inbred Lines ◽  
Puccinia Recondita ◽  
Wheat Leaf Rust ◽  
Susceptible Parent ◽  
Seedling Resistance ◽  
Wheat Leaf

The inheritance of seedling resistance to isolate RLR 213/78 of rye leaf rust (Puccinia recondita f. sp. secalis) and race 30 of wheat leaf rust (P. recondita f. sp. tritici Rob.) was investigated in six inbred lines of rye (Secale cereale). Inbred line UM8116 was used as the susceptible parent in crosses. Inbred lines UM8003, UM8071 and UM8301 each have a single gene and UM8336 and UM8340 each have two genes for resistance to rye leaf rust. For resistance to wheat leaf rust UM8071 has a single gene, UM8003 and UM8340 each have two genes and UM8301 and UM8336 each have three genes. UM8295 is heterogeneous for reaction to both rusts. One of the genes in UM8340 may condition resistance to both rusts. The genes for resistance to RLR 213/78 appear to be independently inherited while some of the genes conferring resistance to race 30 may be identical or very closely linked. The potential of rye as a source of disease resistance for wheat and triticale improvement is discussed.Key words: Secale cereale, disease resistance, wheat leaf rust

scholarly journals Breeding for Flue – Cured Tobacco (Nicotiana Tabacum L) Foliar Pest and Disease Resistance in Zimbabwe: A Review

2019 ◽  
Author(s):  
Justify Gotami Shava ◽  
Susan Richardson Kageler ◽  
Shorai Dari ◽  
Frank Magama ◽  
Dzingai Rukuni
Keyword(s):  
Disease Resistance ◽  
Nicotiana Tabacum ◽  
Financial Resources ◽  
Early 20Th Century ◽  
Quality Loss ◽  
Pests And Diseases ◽  
Field Crops ◽  
Yield And Quality ◽  
Nicotiana Tabacum L ◽  
The World

Since its introduction to Zimbabwean farmers in the early 20th Century, flue –cured tobacco has grown to become one of the most profitable field crops to cultivate in the country. However, pests and diseases have been reported as some of the major contributors to yield and quality loss in the business of tobacco farming in Zimbabwe and across the world reducing the profitability of the tobacco business. This has resulted in large sums of financial resources being invested in research aimed at controlling pests and diseases in different crops. In Zimbabwe millions of litres of pesticides have been pumped into the environment in an effort to control pests and diseases in flue-cured tobacco fields. There have also been efforts to incorporate inherent pest and disease resistance in the varieties of flue-cured tobacco developed in the country since the early 1940s. This paper is a review of the breeding efforts to incorporate pest and disease resistance in the elite flue-cured tobacco germplasm used to develop some of the popular varieties in Zimbabwe.

scholarly journals Field Characterization of Partial Resistance to Gray Leaf Spot in Elite Maize Germplasm

2020 ◽  
Vol 110 (10) ◽  
pp. 1668-1679
Author(s):  
James O. Nyanapah ◽  
Patrick O. Ayiecho ◽  
Julius O. Nyabundi ◽  
Washington Otieno ◽  
Peter S. Ojiambo
Keyword(s):  
Disease Resistance ◽  
Leaf Area ◽  
Plant Development ◽  
Leaf Spot ◽  
Partial Resistance ◽  
Inflection Point ◽  
Inbred Lines ◽  
Gray Leaf Spot ◽  
Diseased Leaf ◽  
Diseased Leaf Area

Forty-eight inbred lines of maize with varying levels of resistance to gray leaf spot (GLS) were artificially inoculated with Cercospora zeina and evaluated to characterize partial disease resistance in maize under field conditions from 2012 to 2014 across 12 environments in western Kenya. Eight measures of disease epidemic—that is, final percent diseased leaf area (FPDLA), standardized area under the disease progress curve (SAUDPC), weighted mean absolute rate of disease increase (ρ), disease severity scale (CDSG), percent diseased leaf area at the inflection point (PDLAIP), SAUDPC at the inflection point (SAUDPCIP), time from inoculation to transition of disease progress from the increasing to the decreasing phase of epidemic increase (TIP), and latent period (LP)—were examined. Inbred lines significantly (P < 0.05) affected all measures of disease epidemic except ρ. However, the proportion of the variation attributed to the analysis of variance model was most strongly associated with SAUDPC (R2 = 89.4%). Inbred lines were also most consistently ranked for disease resistance based on SAUDPC. Although SAUDPC was deemed the most useful variable for quantifying partial resistance in the test genotypes, the proportion of the variation in SAUDPC in each plot was most strongly (R2 = 93.9%) explained by disease ratings taken between the VT and R4 stages of plant development. Individual disease ratings at the R4 stage of plant development were nearly as effective as SAUDPC in discerning the differential reaction of test genotypes. Thus, GLS rankings of inbred lines based on disease ratings at these plant developmental stages should be useful in prebreeding nurseries and preliminary evaluation trials involving large germplasm populations.

scholarly journals Genome editing for plant disease resistance: applications and perspectives

2019 ◽  
Vol 374 (1767) ◽  
pp. 20180322 ◽  
Author(s):  
Kangquan Yin ◽  
Jin-Long Qiu
Keyword(s):  
Disease Resistance ◽  
Genome Editing ◽  
Plant Disease Resistance ◽  
Genetic Improvement ◽  
Plant Disease ◽  
Resistance Breeding ◽  
Global Food Security ◽  
Yield And Quality ◽  
Genome Modifications ◽  
Global Food

Diseases severely affect crop yield and quality, thereby threatening global food security. Genetic improvement of plant disease resistance is essential for sustainable agriculture. Genome editing has been revolutionizing plant biology and biotechnology by enabling precise, targeted genome modifications. Editing provides new methods for genetic improvement of plant disease resistance and accelerates resistance breeding. Here, we first summarize the challenges for breeding resistant crops. Next, we focus on applications of genome editing technology in generating plants with resistance to bacterial, fungal and viral diseases. Finally, we discuss the potential of genome editing for breeding crops that present novel disease resistance in the future. This article is part of the theme issue ‘Biotic signalling sheds light on smart pest management’.

Effectiveness of major resistance genes and identification of new sources for disease resistance in wheat

2011 ◽  
Vol 59 (3) ◽  
pp. 241-248 ◽  
Author(s):  
G. Vida ◽  
M. Cséplő ◽  
G. Gulyás ◽  
I. Karsai ◽  
T. Kiss ◽  
...  
Keyword(s):  
Disease Resistance ◽  
Powdery Mildew ◽  
Leaf Rust ◽  
Resistance Genes ◽  
Rust Resistance ◽  
Genetic Material ◽  
Leaf Rust Resistance ◽  
Wheat Varieties ◽  
Major Resistance Genes ◽  
Greenhouse Tests

Among the factors which determine yield reliability an important role is played by disease resistance. One of the breeding aims in the Martonvásár institute is to develop wheat varieties with resistance to major diseases. The winter wheat varieties bred in Martonvásár are examined in artificially inoculated nurseries and greenhouses for resistance to economically important pathogens. The effectiveness of designated genes for resistance to powdery mildew and leaf rust has been monitored over a period of several decades. None of the designated major resistance genes examined in greenhouse tests is able to provide complete resistance to powdery mildew; however, a number of leaf rust resistance genes provide full protection against pathogen attack (Lr9, Lr19, Lr24, Lr25, Lr28 and Lr35). In the course of marker-assisted selection, efficient resistance genes (Lr9, Lr24, Lr25 and Lr29) have been incorporated into Martonvásár wheat varieties. The presence of Lr1, Lr10, Lr26, Lr34 and Lr37 in the Martonvásár gene pool was identified using molecular markers. New sources carrying alien genetic material have been tested for powdery mildew and leaf rust resistance. Valuable Fusarium head blight resistance sources have been identified in populations of old Hungarian wheat varieties. Species causing leaf spots (Pyrenophora tritici-repentis, Septoria tritici and Stagonospora nodorum) have gradually become more frequent over the last two decades. Tests on the resistance of the host plant were begun in Martonvásár four years ago and regular greenhouse tests on seedlings have also been initiated.

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