scholarly journals A comparison of the genetics of seedling and adult plant resistance to the spot form of net blotch (Pyrenophora teres f. maculata)

2003 ◽  
Vol 54 (12) ◽  
pp. 1387 ◽  
Author(s):  
K. J. Williams ◽  
G. J. Platz ◽  
A. R. Barr ◽  
J. Cheong ◽  
K. Willsmore ◽  
...  
Keyword(s):  
Plant Resistance ◽  
Adult Plant Resistance ◽  
Nematode Resistance ◽  
Cyst Nematode ◽  
Field Resistance ◽  
Adult Plant ◽  
Pyrenophora Teres ◽  
Net Blotch ◽  
Seedling Resistance ◽  
Probable Effect

Spot form of net blotch (SFNB) (Pyrenophora teres f. maculata) is an economically damaging foliar disease of barley in many of the world's cereal-growing areas. The gene Rpt4 that confers seedling resistance to SFNB has been mapped on the long arm of chromosome 7H, but no genes for adult plant resistance (APR) have been identified. A lack of field resistance to SFNB in breeders' lines selected for Rpt4 led us to investigate the genetics of APR to this disease. Five doubled-haploid populations were phenotyped for seedling and adult plant reaction. Markers linked to Rpt4 explained a large part of the seedling variation, but little of the APR. In 2 mapped populations, major quantitative trait loci (QTLs) for APR distal to Rpt4 on chromosome 7H were identified. QTLs contributing to APR on chromosomes 4H or 5H were also identified in each population. Association of the 5H QTL with a gene for cereal cyst nematode resistance and the probable effect of this linkage on the historical development of cultivars with adult plant resistance to SFNB is discussed.

scholarly journals Responses of Barley Cultivars and Lines to Isolates of Pyrenophora teres

Plant Disease ◽  
1998 ◽  
Vol 82 (3) ◽  
pp. 316-321 ◽  
Author(s):  
A. Douiyssi ◽  
D. C. Rasmusson ◽  
A. P. Roelfs
Keyword(s):  
Plant Resistance ◽  
Adult Plant Resistance ◽  
Resistance Breeding ◽  
Adult Plant ◽  
Pyrenophora Teres ◽  
Net Blotch ◽  
Seedling Resistance ◽  
Barley Cultivars ◽  
Pathogenic Variability ◽  
High Level

Net blotch, caused by Pyrenophora teres, is among the most damaging foliar diseases of barley worldwide. A knowledge of the reaction of local cultivars, putative resistant lines, and variability in the net blotch pathogen is necessary to develop a successful resistance breeding program. Disease responses of 38 barley lines to 15 P. teres isolates were studied at the seedling and adult plant stages in the glasshouse, and field responses to net blotch were evaluated at three Moroccan locations. No tested barley was resistant to all isolates, and resistance was apparently of the specific type. Pathogenic variability was great, as none of the 15 isolates were identical. For each isolate tested, a specific high level of resistance was found in one or more host lines. Seedling and adults plants often differed in response to the same isolate. Adult plant resistance was commonly observed in response to isolate I-1, and seedling resistance was more common to isolate I-14. Adult plant resistance of nine lines was undetected in seedling evaluations using isolate I-1. The seedling glasshouse and field responses of the barley lines varied considerably, limiting the value of seedling testing for resistance. Field reactions of resistant and moderately resistant were consistent across the three locations for the lines Heartland, Minn 7, CI 2333, and CI 2549. The variability observed in P. teres and failure to find lines with resistance to all isolates suggests that breeding for resistance should emphasize pyramiding of resistance genes.

Genetics of leaf-rust resistance in three spelt wheats

1994 ◽  
Vol 74 (2) ◽  
pp. 231-233 ◽  
Author(s):  
P. L. Dyck ◽  
E. E. Sykes
Keyword(s):  
Leaf Rust ◽  
Plant Resistance ◽  
Rust Resistance ◽  
Adult Plant Resistance ◽  
Leaf Rust Resistance ◽  
Field Resistance ◽  
Adult Plant ◽  
Seedling Resistance ◽  
Field Reaction ◽  
High Level

The inheritance of leaf-rust resistance was studied in three accessions of spelt wheat (Triticum aestivum ssp. spelta L.). Accession 7831 has a gene for seedling resistance to leaf rust that is linked with Lr33 (5.4 ± 1.05%), which is known to he on the long arm of chromosome 1B. This gene, which was either recessive or partially dominant, is designated Lr44, and because of its field reaction, should be useful in breeding rust-resistant wheats. Accession 7839 may also have this gene and an additional gene that in the seedling stage conditioned a type 2 infection to many races but little field resistance. Accessions 7831, 7839 and 7825 also have possibly in common a gene for adult-plant resistance. This gene, which did not give a high level of field resistance, was independent of Lr12, Lr13, Lr22, Lr34 and Lr35, other genes for adult-plant resistance. Key words:Triticum, wheat, leaf-rust resistance

Seedling resistances to rust diseases in international triticale germplasm

2010 ◽  
Vol 61 (12) ◽  
pp. 1036 ◽  
Author(s):  
J. Zhang ◽  
C. R. Wellings ◽  
R. A. McIntosh ◽  
R. F. Park
Keyword(s):  
Leaf Rust ◽  
Stripe Rust ◽  
Plant Resistance ◽  
Stem Rust ◽  
Rust Resistance ◽  
Adult Plant Resistance ◽  
Stem Rust Resistance ◽  
Adult Plant ◽  
Seedling Resistance ◽  
Rust Diseases

Seedling resistances to stem rust, leaf rust and stripe rust were evaluated in the 37th International Triticale Screening Nursery, distributed by the International Wheat and Maize Improvement Centre (CIMMYT) in 2005. In stem rust tests, 12 and 69 of a total of 81 entries were postulated to carry Sr27 and SrSatu, respectively. When compared with previous studies of CIMMYT triticale nurseries distributed from 1980 to 1986 and 1991 to 1993, the results suggest a lack of expansion in the diversity of stem rust resistance. A total of 62 of 64 entries were resistant to five leaf rust pathotypes. In stripe rust tests, ~93% of the lines were postulated to carry Yr9 alone or in combination with other genes. The absence of Lr26 in these entries indicated that Yr9 and Lr26 are not genetically associated in triticale. A high proportion of nursery entries (63%) were postulated to carry an uncharacterised gene, YrJackie. The 13 lines resistant to stripe rust and the 62 entries resistant to leaf rust represent potentially useful sources of seedling resistance in developing new triticale cultivars. Field rust tests are needed to verify if seedling susceptible entries also carry adult plant resistance.

Inheritance of resistance to stem rust in 'Bonza', 'Chris', 'FKN-II-50-17', 'MRFY', 'Thatcher', 'Marquillo', and 'Hope' wheats

Genome ◽  
1988 ◽  
Vol 30 (2) ◽  
pp. 269-276
Author(s):  
M. Padidam ◽  
D. R. Knott
Keyword(s):  
Triticum Aestivum ◽  
Plant Resistance ◽  
Stem Rust ◽  
Adult Plant Resistance ◽  
Major Gene ◽  
Triticum Aestivum L ◽  
Adult Plant ◽  
Puccinia Graminis ◽  
Seedling Resistance ◽  
Minor Genes

Resistance to stem rust (Puccinia graminis Pers. f. sp. tritici Eriks, and Henn.), particularly adult plant resisitance to race 15B-1, was studied in seven wheat (Triticum aestivum L.) cultivars or lines: 'Bonza', 'Chris', 'FKN-II-50-17', 'MRFY', 'Thatcher', 'Marquillo', and 'Hope'. Each of the seven was crossed with a susceptible parent and either F4- or F5-derived lines developed by single seed descent. All of the lines were tested with race 15B-1 in field nurseries. Lines derived from parents carrying seedling resistance to race 15B-1 were also tested as seedlings in the greenhouse with race 15B-1, and in some cases races 56, 29, and C65. The data indicated that 'Bonza' carries Sr6, probably Sr5, an unidentified gene giving resistance to race 56, two unidentified genes for resistance to race C65, and two minor genes that combine to produce intermediate adult plant resistance. 'Chris' carries Sr5, Sr7a, Sr8a, and Sr12. In addition, it may have three minor genes for adult plant resistance. 'FKN-II-50-17' carries Sr6 and may have four minor genes that combine to produce moderate adult plant resistance. 'MRFY', which is seedling susceptible to race 15B-1, carries Sr9b, possibly Sr5, plus an unidentified gene for resistance to C65. In addition, it appears to have one major gene for adult plant resistance plus two or more minor genes. 'Thatcher', 'Marquillo', and 'Hope' had only limited resistance to race 15B-1 in the field and no genetic analysis of their crosses was possible. The four parents that had good resistance to race 15B-1 in the field, 'Bonza', 'Chris', 'FKN-II-50-17', and 'MRFY', all carry minor genes for adult plant resistance that had little effect individually but produced moderate resistance when combined. The genes Sr5 and Sr9b, which have no effect on resistance to 15B-1 is seedlings, were found to significantly increase resistance in adult plants in the field.Key words: stem rust, Puccinia graminis tritici, wheat, Triticum aestivum, adult plant rust resistance.

THE GENETIC ANALYSIS OF TWO INTERSPECIFIC SOURCES OF LEAF RUST RESISTANCE AND THEIR EFFECT ON THE QUALITY OF COMMON WHEAT

1988 ◽  
Vol 68 (3) ◽  
pp. 633-639 ◽  
Author(s):  
P. L. DYCK ◽  
O. M. LUKOW
Keyword(s):  
Triticum Aestivum ◽  
Protein Content ◽  
Leaf Rust ◽  
Plant Resistance ◽  
Rust Resistance ◽  
Adult Plant Resistance ◽  
Leaf Rust Resistance ◽  
Adult Plant ◽  
Seedling Resistance ◽  
Kernel Protein

Gene Lr29 transferred from Agropyron elongatum to chromosome 7D of wheat and gene LrVPM transferred from VPM1 both segregated as single genes for seedling resistance to leaf rust when backcrossed into common wheat (Triticum aestivum). Although the seedling resistance of the VPM lines was intermediate, their adult plant resistance was excellent. This resistance was not on chromosome 7D. The VPM lines also had seedling and adult plant resistance to stem rust. Resistant backcross lines with either Lr29 or LrVPM had higher kernel protein levels than did susceptible sister lines under both rust and rust-free conditions. Although this higher protein content was associated with weaker dough mixing properties, the remix loaf volume remained constant. Leaf rust infection had a detrimental effect on grain yield and kernel weight and on wheat quality as shown by decreased kernel protein content and farinograph absorption. Dough mixing strength was higher for the rust infected lines than the rust resistant lines.Key words: Triticum aestivum, wheat (spring), leaf rust resistance, protein content, breadmaking quality

scholarly journals Seedling and Adult Plant Resistance to Powdery Mildew in Chinese Bread Wheat Cultivars and Lines

Plant Disease ◽  
2005 ◽  
Vol 89 (5) ◽  
pp. 457-463 ◽  
Author(s):  
Z. L. Wang ◽  
L. H. Li ◽  
Z. H. He ◽  
X. Y. Duan ◽  
Y. L. Zhou ◽  
...  
Keyword(s):  
Powdery Mildew ◽  
Bread Wheat ◽  
Resistance Genes ◽  
Plant Resistance ◽  
Adult Plant Resistance ◽  
The United States ◽  
Adult Plant ◽  
Wheat Cultivars ◽  
Seedling Resistance ◽  
Progress Curve

Powdery mildew, caused by Blumeria graminis f. sp. tritici, is a widespread wheat disease in China. Identification of race-specific genes and adult plant resistance (APR) is of major importance in breeding for an efficient genetic control strategy. The objectives of this study were to (i) identify genes that confer seedling resistance to powdery mildew in Chinese bread wheat cultivars and introductions used by breeding programs in China and (ii) evaluate their APR in the field. The results showed that (i) 98 of 192 tested wheat cultivars and lines appear to have one or more resistance genes to powdery mildew; (ii) Pm8 and Pm4b are the most common resistance genes in Chinese wheat cultivars, whereas Pm8 and Pm3d are present most frequently in wheat cultivars introduced from CIMMYT, the United States, and European countries; (iii) genotypes carrying Pm1, Pm3e, Pm5, and Pm7 were susceptible, whereas those carrying Pm12, Pm16, and Pm20 were highly resistant to almost all isolates of B. graminis f. sp. tritici tested; and (iv) 22 genotypes expressed APR. Our data showed that the area under the disease progress curve, maximum disease severity on the penultimate leaf, and the disease index are good indicators of the degree of APR in the field. It may be a good choice to combine major resistance genes and APR genes in wheat breeding to obtain effective resistance to powdery mildew.

The identification of QTLs for adult plant resistance to leaf scald in barley

2006 ◽  
Vol 57 (9) ◽  
pp. 961 ◽  
Author(s):  
Judy Cheong ◽  
Kevin Williams ◽  
Hugh Wallwork
Keyword(s):  
Plant Resistance ◽  
Adult Plant Resistance ◽  
Bulked Segregant Analysis ◽  
Natural Infection ◽  
Durable Resistance ◽  
Adult Plant ◽  
Resistance Locus ◽  
Seedling Resistance ◽  
Leaf Scald ◽  
Dh Lines

Barley leaf scald disease, caused by the fungal pathogen Rhynchosporium secalis, can be economically damaging, causing both yield losses and lower quality from reduced grain size. Most genetic studies of scald resistance have concentrated on seedling reactions either because of a lack of access to field screening resources or else because of the more definitive phenotype obtained at the seedling stage. However, understanding the genetics of adult plant resistance (APR) to leaf scald could help to produce more durable resistance to this disease. APR to leaf scald in a Chebec/Harrington population (120 doubled haploid (DH) lines) and a Mundah/Keel population (95 DH lines) was determined at Turretfield, South Australia, in 2004. Two different conditions of scald infection were used for Chebec/Harrington, natural infection and inoculation with 2 known scald isolates, whereas Mundah/Keel was inoculated with 2 known isolates. Quantitative trait loci (QTLs) for scald resistance were identified using a previously published Chebec/Harrington map. Three QTLs (on chromosomes 7HS, 7HL, and 6HS) were identified using the natural infection data and one QTL on chromosome 6HL using the inoculated plant data. Two QTLs were identified on chromosome 3HL and 6HS, respectively, using a partial map of Mundah/Keel. An unmapped Schooner/O’Connor population, consisting of 116 DH lines, was also phenotyped for adult plant resistance to scald using natural infection at Turretfield in 2001. Bulked-segregant analysis was used to identify molecular markers linked to a scald resistance locus in the barley cultivar O’Connor on chromosome 6HS, at the same location as the QTLs identified from Harrington and Keel. Six of the QTLs for APR to leaf scald identified in this study were co-located with previously identified seedling resistance genes.

scholarly journals Durability of resistance to stripe rust in the wheat cultivar Claire in New Zealand

2011 ◽  
Vol 64 ◽  
pp. 17-24
Author(s):  
S.F. Chng ◽  
M.G. Cromey ◽  
S.C. Shorter
Keyword(s):  
New Zealand ◽  
Stripe Rust ◽  
Plant Resistance ◽  
Field Experiments ◽  
Adult Plant Resistance ◽  
Puccinia Striiformis ◽  
Durable Resistance ◽  
Adult Plant ◽  
Seedling Resistance ◽  
Differential Cultivars

Host resistance is the most economical way to manage wheat stripe rust caused by Puccinia striiformis f sp tritici The cultivar Claire was released in 1999 and until recently remained highly resistant to the disease in the United Kingdom While Claire was considered durably resistant to stripe rust in New Zealand it is now categorised as moderately susceptible The present study investigated whether racespecific resistance was responsible for this breakdown in resistance and whether cv Claire retains useful durable resistance A rust culture from cv Claire was compared with a pre2005 culture on a set of differential cultivars The seedling resistance in cv Claire was racespecific Greenhouse and field experiments suggest that the adult plant resistance in cv Claire has been reduced in the presence of a more virulent stripe rust population Remaining adult plant resistance is insufficient to provide adequate control of stripe rust in New Zealand wheat crops

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