Effect of Leaf Rust Resistance Gene Lr34 on Grain Yield and Agronomic Traits of Spring Wheat (original) (raw)
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Characterization of Adult-Plant Resistance to Leaf Rust of Wheat Conferred by the Gene Lr22a
Plant Disease, 1987
ReseaRch W heat (Triticum aestivum L.) is a major staple food worldwide, with harvested area of >220 million ha from 2014 to 2016 (USDA-ERS, 2017). During the last decade in Mexico, wheat has been grown on 713,000 ha annually with a yield of 5.2 t ha −1 (Calvo-Salazar et al., 2015). Leaf rust and stripe rust, caused by Puccinia triticina Erikss. (Pt) and P. striiformis Westend. f. sp. tritici (Pst), respectively, are two major diseases that threaten wheat production worldwide. For example, yield losses caused by both rusts were up to 60% on susceptible cultivars (Herrera-Foessel et al., 2006; Vergara-Díaz et al., 2015). Breeding and cultivation
South African Journal of Plant and Soil, 1997
Monogenic resistance in wheat (Triticum aestivum L.) to leaf rust, caused by Puccinia recondita Rob. ex. Desm. f. sp. tritici, h•as generally not been durable. Durable resistance, as well as an improved expression of resistance, have been associated with Lrgene combinations. In this study, the assumption that Lr12 and Lr13 may interact to condition improved resistance to leaf rust, was investigated. Four Thatcher (T c) x RL6011 F3 lines (13/12-3, 13/12-9, 13/12-19 and 13/12-40), homozygous for both Lr13 and Lr12, were selected and their leaf rust resistance compared with the parents (CT263 [=TcLr13] and RL6011 [=TcLr12]), the single gene lines Tc/13-22 and TC/12-16, and Thatcher. In addition to infection type studies in seedlings and adult plants, lines were compared according to macroscopic components of resistance, as well as disease ratings in the field. Flag leaf infection type studies showed that Lr12 is effective against most pathotypes of P. recondita f. sp. tritici occurring in South Africa. Conversely, Lr13 is ineffective against the dominant pathotypes, implying that the gene has no value as a monogenic source of resistance. Based on the fact that several pathotypes are avirulent to these genes, they should be manipulated with relative ease in local breeding programmes directed at utilizing these sources in combination with other Lr genes. Infection types on the flag leaves of lines carrying both Lr12 and Lr13 often displayed chlorosis and necrosis. These ratings on primary and flag leaves, as well as the quantitative components latent period, uredium density and uredium size, did not indicate clear differences between the digenic lines and the most resistant parent. In the absence of a pathotype virulent to both genes, the combination lines were resistant in the field. Data obtained were not conclusive in suggesting pronounced resistance enhancement due to combining Lr12 with Lr13. Enkelgeen-weerstand in koring (Tn"ticum aestivum L.) teen blaarroes, veroorsaak deur die swam Puccinia recondita Rob. ex. Desm. f. sp. tritici, is dikwels nie volhoubaar nie. Meer standhoudende weerstand, asook verbeterde vlakke van weerstand, kan verkry word deur weerstandsgene te kombineer. In hierdie studie is die aanname ondersoek dat die interaksie tussen Lr12 en Lr13 verhoogde weerstand teen blaarroes tot gevolg kan he. Vier F31yne in die genetiese agtergrond van Thatcher (Tc) (13/12-3,13/12-9,13/12-19 en 13/12-40), homosigoties vir beide Lr12 en Lr13, is geselekteer en met die ouers (CT263 [=TcLr13] en RL6011 [=TcLr12]), die enkelgeenlyne Tc/13-22 en Tc/12-16, en Thatcher vergelyk ten opsigte van blaarroesbestandheid. Behalwe vir die bepaling van infeksietipes, is makroskopiese weerstandskomponente gekwantifiseer en siekteramings in die veld gedoen. Vlagblaarinfeksietipes het getoon dat Lr12 effektief is teen meeste Suid-Afrikaanse patotipes van P. recondita f. sp. tritici. Die dominante patotipes is virulent tot Lr13. Die voorkoms van verskeie avirulente patotipes beteken dat die gene met refatiewe gemak in plaaslike koringveredefingsprogramme met ander Lrgene gekombineer kan word. Chlorose en nekrose was algemene kenmerke van infeksietipes op vlagblare van die kombinasielyne. Infeksietipes tydens beide saailing-en volwasseplantgroeistadia, sowel as die kwantitatiewe weerstandskomponente latente periode, urediumdigtheid en urediumgrootte, het nie betekenisvol verskil vir die enkefgeen-en kombinasielyne nie. In die afwesigheid van 'n patotipe met virufensie teenoor beide gene, was die kombinasielyne weerstandbiedend in die veld. Geen oortuigende verhoging in blaarroesweerstand kon aan die kombinering van Lr12 met Lr13 toegeskryf word nie.
Crop Science, 2008
Puccinia recondita f. sp. tritici) is one of the most important diseases limiting global production of hexaploid or common wheat (Triticum aestivum L.). In the last decade (1997-2006), annual losses in the United States due to this pathogen have averaged 575,000 t for winter wheat and 202,000 t for spring wheat (Long, 2007). Therefore, the deployment of leaf rust (Lr) resistance genes into commercial cultivars is still an important objective of most wheat breeding programs. In addition, the incorporation of genetic resistance reduces the need for fungicide applications, decreasing production costs and environmental pollution. Wild Triticeae species have been extensively used to expand the pool of resistance genes in cultivated wheat and account for approximately half of the 55 named Lr resistance genes (Friebe et al., 1996; Knott, 1989; McIntosh et al., 2003, 2006). The eff orts to expand the number of Lr resistance genes are off set by the continuous evolution of new races of the pathogen. New P. triticina races virulent on resistance genes Lr9, Lr16, Lr17, Lr24, and Lr26
Response of wheat genotypes against leaf rust (Puccinia triticina) under field conditions
Plant Protection , 2019
The current research was planned to evaluate the response of 37 wheat (Triticum aestivum) genotypes against leaf rust resistance under field conditions during 2017-18. Areas under disease progress curve (AUDPC) of all the varieties were calculated. Leaf rust severity response was variable among the tested genotypes. Out of thirty-seven genotypes, five wheat lines i.e. 17BT007, 17BT013, 16BT008, 16BT010 and 16BT011 were immune. Seven lines were found to be resistant with AUDPC values ranged from 1 to 199. Response of ten lines was moderately resistant while five lines were categorized as moderately susceptible. Ten genotypes exhibited susceptible response against leaf rust with more than 600 AUDPC value. High values above 600 of AUDPC showed greater incidence of leaf rust on wheat plants while lower AUDPC values indicated resistance to leaf rust. Present research provided the resistant wheat lines to the breeders to incorporate in their breeding program against leaf rust.
Screening of wheat genotypes for leaf rust resistance along with grain yield
Annals of Agricultural Sciences, 2015
Leaf rust caused by Puccinia triticina Eriks., is one of the main diseases of wheat (Triticum aestivum L.) in Egypt, causing up to 50% of yield losses. Genetic resistance is the most economic and effective means of reducing yield losses caused by the disease. However, breeding genotypes for disease resistance is a continuous process and plant breeders need to add new effective sources to their breeding materials. Among 42 Egyptian wheat varieties screened for leaf rust resistance, only 9 varieties (Sakha94,
Plant Disease, 2006
Leaf rust, caused by Puccinia triticina, is an important disease of durum wheat (Triticum turgidum) in many countries. We compared the effectiveness of different types of resistance in International Maize and Wheat Improvement Center-derived durum wheat germ plasm for protecting grain yield and yield traits. In all, 10 durum wheat lines with race-specific resistance, 18 with slow-rusting resistance, and 2 susceptible were included in two yield loss trials sown on different planting dates in Mexico with and without fungicide protection under high disease pressure. Eight genotypes with race-specific resistance were immune to leaf rust. Durum wheat lines with slow-rusting resistance displayed a range of severity responses indicating phenotypic diversity. Mean yield losses for susceptible, race-specific, and slow-rusting genotypes were 51, 5, and 26%, respectively, in the normal sowing date trial and 71, 11, and 44% when sown late. Yield losses were associated mainly with a reduction in...
Breeding wheat for leaf rust resistance: past, present and future
review article, 2023
Leaf rust of wheat caused by (Puccinia triticina Eriks) proliferate under optimum weather conditions and causes severe damage. Diseases appeared in form of epidemics pose a real threat to food security rising the cost of food production. Breeding for development of resistant varieties against disease has advantages for ecological and monetary reasons, predominantly for peasants in the developing world. Sufficient research work has been conducted regarding pathogen host interaction mechanism. Two mechanisms of resistance are acquainted very well. Complete resistance function from seedling to adult growth stages whereas partial resistance becomes effective at the prebooting stage and is more durable. Eighty leaf rust-resistant genes have been documented. Among these leaf rust-resistant genes Lr12,
Genetics of Leaf Rust Resistance in the Winter Wheat Line CI13227
Crop Science, 2012
L eaf rust, caused by Puccinia triticina Eriks., is a common disease of wheat worldwide (Roelfs et al., 1992). Although many different leaf rust resistance genes have been designated (McIntosh et al., 2010), most of these genes condition race-specifi c resistance that has been overcome by virulent races of P. triticina. In the United States, P. triticina races are selected for virulence in response to specifi c resistance genes in released wheat cultivars (Kolmer et al., 2011). A few genes such as Lr34 (Dyck, 1987) and Lr46 (Singh et al., 1998) that condition adult plant resistance (APR) to all current phenotypes of P. triticina have provided longer lasting resistance, although these genes by themselves do not condition high levels of resistance. Wheat cultivars that have "slow rusting" resistance to leaf rust have been advocated as sources of durable resistance to leaf rust (Caldwell, 1968). Component traits of this resistance have been defi ned in epidemiological terms of latent period (time in days or hours needed for rust sporulation after infection), infection efficiency (uredinia cm −2 leaf), spore production per uredinia, size of uredinia, area under the disease progress curve, and infection rate
Phenotypic association of adult-plant resistance to leaf and stripe rusts in wheat
Canadian Journal of Plant Pathology, 2005
Association of resistance to multiple diseases is of interest to plant breeders as it simplifies the breeding process. Phenotypic association of adult-plant resistance to leaf and stripe rusts, caused by Puccinia triticina and Puccinia striiformis f. sp. tritici, respectively, was studied in F 5 wheat lines derived from a diallel cross involving one susceptible and five resistant genotypes. Resistance in the parental genotypes was formerly identified as being conditioned by the Lr34/Yr18 linkage on chromosome arm 7DS, in addition to at least two to three genes with additive effects. Adult-plant resistance to leaf rust was found to be closely associated with resistance to stripe rust in the wheat genotypes examined in this study. Results indicated that genes other than Lr34/Yr18 were also either linked or pleiotropic for resistance to both diseases. This linkage or pleiotropic effect, however, did not seem to occur in every instance. Resistance genes other than Lr34/Yr18 were estimated to have contributed to 40% and 43% reductions in severity of leaf and stripe rusts, respectively, while lines with a phenotype of leaf-tip necrosishad, on average, 30.5% and 20.8% less severity for leaf and stripe rusts, respectively.