scholarly journals Characterization and Mapping of Spot Blotch in Triticum durum–Aegilops speltoides Introgression Lines Using SNP Markers

2021 ◽  
Vol 12 ◽  
Author(s):  
Jashanpreet Kaur ◽  
Jaspal Kaur ◽  
Guriqbal Singh Dhillon ◽  
Harmandeep Kaur ◽  
Jasvir Singh ◽  
...  

Spot blotch (SB) of wheat is emerging as a major threat to successful wheat production in warm and humid areas of the world. SB, also called leaf blight, is caused by Bipolaris sorokiniana, and is responsible for high yield losses in Eastern Gangetic Plains Zone in India. More recently, SB is extending gradually toward cooler, traditional wheat-growing North-Western part of the country which is a major contributor to the national cereal basket. Deployment of resistant cultivars is considered as the most economical and ecologically sound measure to avoid losses due to this disease. In the present study, 89 backcross introgression lines (DSBILs) derived from Triticum durum (cv. PDW274-susceptible) × Aegilops speltoides (resistant) were evaluated against SB for four consecutive years, 2016–2020. Phenotypic evaluation of these lines showed a continuous variation in disease severity indicating that the resistance to SB is certainly quantitative in nature. Phenotypic data of DSBILs were further used for mapping QTLs using SNPs obtained by genotyping by sequencing. To identify QTLs stable across the environments, Best Linear Unbiased Estimates (BLUEs) and Predictions (BLUPs) were used for mapping QTLs based on stepwise regression-based Likelihood Ratio Test (RSTEP-LRT) for additive effect of markers and single marker analysis (SMA). Five QTLs, Q.Sb.pau-2A, Q.Sb.pau-2B, Q.Sb.pau-3B, Q.Sb.pau-5B, and Q.Sb.pau-6A, linked to SB resistance were mapped across chromosomes 2A, 2B, 3B, 5B, and 6A. Genes found adjacent to the SNP markers linked to these QTLs were literature mined to identify possible candidate genes by studying their role in plant pathogenesis. Further, highly resistant DSBIL (DSBIL-13) was selected to cross with a susceptible hexaploidy cultivar (HD3086) generating BC2F1 population. The QTL Q.Sb.pau-5B, linked to SNP S5B_703858864, was validated on this BC2F1 population and thus, may prove to be a potential diagnostic marker for SB resistance.

2020 ◽  
Vol 18 (4) ◽  
pp. 211-221
Author(s):  
Guriqbal Singh Dhillon ◽  
Satinder Kaur ◽  
Niranjan Das ◽  
Rohtas Singh ◽  
Jesse Poland ◽  
...  

AbstractWheat, a major food crop, faces significant yield constraints due to losses caused by various diseases, especially rusts and powdery mildew. Since the causal organisms are always evolving, there is a never-ending hunt for new genes/quantitative trait loci (QTLs) for resistance to control the damage. For this purpose, Triticum durum–Aegilops speltoides backcross introgression lines (DS-BILs) developed in our wide hybridization programme were screened against stripe rust and powdery mildew at both seedling and adult plant stages. DS-BILs showed complete to moderate resistance at the adult plant stage while varying resistance and susceptibility at the seedling stage. A total of 1095 single-nucleotide polymorphisms (SNPs) identified on 14 chromosomes of T. durum, using genotyping by sequencing, were used for QTL mapping. Eleven unique QTLs, across six chromosomes (chr1B, chr2A, chr2B, chr3B, chr6B and chr7B) were identified for resistance, four QTLs for field mixture of stripe rust pathotypes, two QTLs for stripe rust pathotype 78S84 and five QTLs for field mixture of powdery mildew pathotypes using stepwise regression-based likelihood ratio test for additive effect of markers and single-marker analysis. Eleven DS-BILs carrying multiple QTLs were identified which will serve as a useful resource to transfer the respective resistance to susceptible cultivars to develop all stage resistant elite cultivars where QTL for stripe rust resistance QYrAs.pau-2A.1 (LOD 3.8, PVE 24.51 linked to SNP S2A_16016633) and QTL for powdery mildew resistance QPmAs.pau-6B (logarithm of the odds (LOD) 3.2, phenotypic variation explained (PVE) 17.75 linked to SNP S6B_26793381) are major targets of the transfer.


2021 ◽  
Vol 43 (2) ◽  
Author(s):  
M. El Amine Kouadri ◽  
A. Amine Bekkar ◽  
S. Zaim

2021 ◽  
pp. 1-8
Author(s):  
Deep Shikha ◽  
Chandani Latwal ◽  
Elangbam Premabati Devi ◽  
Anupama Singh ◽  
Pawan K. Singh ◽  
...  

Abstract Genetic resources are of paramount importance for developing improved crop varieties, particularly for biotic and abiotic stress tolerance. Spot blotch (SB) is a destructive foliar disease of wheat prevalent in warm and humid regions of the world, especially in the eastern parts of South Asia. For the management of this disease, the most effective measure is the development of resistant cultivars. Thus, the present investigation was carried out to confirm SB resistance in 200 germplasm accessions based on phenotypic observations and molecular characterization. These elite breeding lines obtained from the International Centre for Maize and Wheat Improvement, Mexico, are developed deploying multiple parentages. These lines were screened for SB resistance in the field under artificially created epiphytotic conditions during 2014–15 and 2015–16 along with two susceptible checks (CIANO T79 and Sonalika) and two resistant checks (Chirya 3 and Francolin). Eighty-two out of 200 germplasm accessions were found resistant to SB and resistance in these lines was confirmed with a specific SSR marker Xgwm148. Three accessions, VORONA/CNO79, KAUZ*3//DOVE/BUC and JUP/BJY//URES/3/HD2206/HORK//BUC/BUL were observed possessing better resistance than the well-known SB-resistant genotype Chirya3. These newly identified resistant lines could be used by wheat breeders for developing SB-resistant wheat varieties.


2020 ◽  
Vol 110 (2) ◽  
pp. 440-446 ◽  
Author(s):  
Yueqiang Leng ◽  
Mingxia Zhao ◽  
Jason Fiedler ◽  
Antonín Dreiseitl ◽  
Shiaoman Chao ◽  
...  

Spot blotch (SB) caused by Bipolaris sorokiniana and powdery mildew (PM) caused by Blumeria graminis f. sp. hordei are two important diseases of barley. To map genetic loci controlling susceptibility and resistance to these diseases, a mapping population consisting of 138 recombinant inbred lines (RILs) was developed from the cross between Bowman and ND5883. A genetic map was constructed for the population with 852 unique single nucleotide polymorphism markers generated by sequencing-based genotyping. Bowman and ND5883 showed distinct infection responses at the seedling stage to two isolates (ND90Pr and ND85F) of Bipolaris sorokiniana and one isolate (Race I) of Blumeria graminis f. sp. hordei. Genetic analysis of the RILs revealed that one major gene (Scs6) controls susceptibility to Bipolaris sorokiniana isolate ND90Pr, and another major gene (Mla8) confers resistance to Blumeria graminis f. sp. hordei isolate Race I, respectively. Scs6 was mapped on chromosome 1H of Bowman, as previously reported. Mla8 was also mapped to the short arm of 1H, which was tightly linked but not allelic to the Rcs6/Scs6 locus. Quantitative trait locus (QTL) analysis identified two QTLs, QSbs-1H-P1 and QSbs-7H-P1, responsible for susceptibility to spot blotch caused by Bipolaris sorokiniana isolate ND85F in ND5883, which are located on chromosome 1H and 7H, respectively. QSbs-7H-P1 was mapped to the same region as Rcs5, whereas QSbs-1H-P1 may represent a novel allele conferring seedling stage susceptibility to isolate ND85F. Identification and molecular mapping of the loci for SB susceptibility and PM resistance will facilitate development of barley cultivars with resistance to the diseases.


2012 ◽  
Vol 64 (3) ◽  
pp. 93-102
Author(s):  
Irena Kiecana ◽  
Leszek Rachoń ◽  
Elżbieta Mielniczuk ◽  
Grzegorz Szumiło

Investigations were carried out in 2007-2009 on the plots of the Felin Experimental Station belonging to the University of Life Science in Lublin. The studies comprised two cultivation lines of durum wheat (<i>Triticum durum</i> L.): STH 716 and STH 717, as well as the 'Tonacja' cultivar of common wheat (<i>T. aestivum</i> ssp. <i>vulgare</i> L.). Two levels of chemical protection were applied in the cultivation: minimal and complex protection. Infection of wheat roots and stem bases was recorded in each growing season at hard dough stage (87 in Tottman's scale, 1987). After three years of study, the mean disease indexes for the analyzed wheat genotypes in the experimental treatment with minimal protection were 31.13, 30.43 and 38.83 for, respectively, the 'Tonacja' cultivar and the cultivation lines of <i>T. durum</i> STH 716 and STH 717. In the experimental combination with complex protection, after three years of study the disease indexes ranged from 25.26 (<i>T. durum</i> STH 716) to 30.83 (<i>T. durum</i> STH 717). The results of mycological analysis of diseased plants showed that <i>Fusarium</i> spp., especially <i>F. culmorum</i>, <i>F. avenaceum</i> as well as <i>Bipolaris sorokiniana</i> and <i>Rhizoctonia solani</i>, caused root rot and necrosis of wheat stem bases. The analyzed chemical protection levels did not significantly influence grain yield of the investigated genotypes of <i>T. aestivum</i> and <i>T. durum</i>.


Plant Disease ◽  
2021 ◽  
Author(s):  
Danilo Neves ◽  
Bill Bruening ◽  
Carrie A Knott ◽  
Chad Lee ◽  
Carl Bradley

The Kentucky distilling industry ranks as one of the state’s largest industries and continues to expand. In 2017, the Kentucky distilling industry was responsible for approximately $235 million in state and local tax revenues (Coomes and Kornstein, 2019). Rye (Secale cereale L.) grains are a vital component for production of some distilled spirits. Although winter rye is produced on relatively few hectares in Kentucky currently, a recent initiative has supported expanding production to help meet the growing demand of local distilleries. University of Kentucky winter rye research field trials were visited in Caldwell and Logan Counties, KY in May 2018, and in Fayette County, KY in May 2019. Leaves were collected that had dark brown, oval to irregular-shaped lesions with definite margins and yellow halos. Symptoms were present on approximately 50% to 80% of the flag leaves, with severity ranging from 5% to 30% of the flag leaf area affected. Leaves were surface-disinfested by soaking in a 2% NaOCl solution for 1 min and rinsed twice in sterilized water and then placed in a humidity chamber (plastic bag with moist paper towels) at room temperature (approximately 24°C) to induce fungal sporulation. Seventeen single-spore isolates were obtained and stored at -80°C in 15% glycerol solution. Isolates were grown on potato dextrose agar under 12 h cycles of white light/darkness for 5 days. Colonies were gray to black. Conidia that formed were mostly straight or slightly curved, dark olivaceous brown, 3-7 septate, and 41.0-90.4 × 15.2-29.3 µm. Based on the symptoms observed on the collected leaves and these morphological characteristics similar to those described by Chang and Hwang (2000) and Manamgoda et al. (2014), the fungus was tentatively identified as Bipolaris sorokiniana (Sorokin) Shoemaker. The sequence of internal transcribed spacer regions (ITS) and glyceraldehyde 3-phosphate dehydrogenase (GAPDH) were used to identify three isolates (18Bs004, 18Bs111 and 19Bs064) using primer ITS1/ITS4 (White et al. 1990) and GPD1/GPD2 (Berbee et al. 1999), respectively. The sequences were deposited in GenBank with accession numbers MT457817, MT457818 and MZ066635 for ITS sequences and MZ073644 to MZ073646 for GAPDH sequences. BLAST searches with ITS and GAPDH sequences matched 100% identity (344/344 bp and 515/515 bp for ITS and GAPDH sequences, respectively) to B. sorokiniana (GenBank accession No. MT254731 and MH844813, respectively). To prove pathogenicity, a conidial suspension (1 × 105 conidia/ml) was used to inoculate 15-day-old cultivar ‘Serafino’ winter rye plants in the greenhouse. Leaves of 8 plants were inoculated with 50 ml of the conidial suspension using a spray bottle. Plants were covered with a transparent plastic bag for 48 h, and symptoms were observed 10 days after inoculation. Leaf lesions, similar to those described above, were present on all inoculated plants, but no symptoms were observed on non-inoculated control plants. Bipolaris sorokiniana was reisolated from symptomatic leaves and the identity of the pathogen was confirmed based on the morphology previously described. To our knowledge, this is the first report of spot blotch caused by B. sorokiniana on winter rye in Kentucky, but B. sorokiniana has been reported on rye in the neighboring state of Virginia (Roane 2009). Kentucky produces approximately 150,000 and 4,000 ha of winter wheat (Triticum aestivum) and winter barley (Hordeum vulgare) annually, respectively, which are both known hosts of B. sorokiniana (Kumar et al. 2002). An isolate of B. sorokiniana from rye was reported by Ghazvini and Tekauz (2007) to be less virulent on barley differential lines. Further research is needed to better understand spot blotch distribution, susceptibility in winter rye cultivars, and potential yield and quality loss implications in winter rye production and end use. It is unknown how susceptible various winter rye cultivars grown in Kentucky are to spot blotch.


Agronomy ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1992
Author(s):  
Hafid Aberkane ◽  
Ahmed Amri ◽  
Bouchra Belkadi ◽  
Abdelkarim Filali-Maltouf ◽  
Jan Valkoun ◽  
...  

Durum wheat (Triticum turgidum subsp. durum) is mostly grown in Mediterranean type environments, characterized by unpredictable rainfall amounts and distribution, heat stress, and prevalence of major diseases and pests, all to be exacerbated with climate change. Pre-breeding efforts transgressing adaptive genes from wild relatives need to be strengthened to overcome these abiotic and biotic challenges. In this study, we evaluated the yield stability of 67 lines issued from interspecific crosses of Cham5 and Haurani with Triticum dicoccoides, T. agilopoides, T. urartu, and Aegilops speltoides, grown under 15 contrasting rainfed and irrigated environments in Morocco, and heat-prone conditions in Sudan. Yield stability was assessed using parametric (univariate (e.g., Bi, S2di, Pi etc) and multivariate (ASV, SIPC)) and non-parametric (Si1, Si2, Si3 and Si6) approaches. The combined analysis of variance showed the highly significant effects of genotypes, environments, and genotype-by-environment interaction (GEI). The environments varied in yield (1370–6468 kg/ha), heritability (0.08–0.9), and in their contribution to the GEI. Several lines derived from the four wild parents combined productivity and stability, making them suitable for unpredictable climatic conditions. A significant advantage in yield and stability was observed in Haurani derivatives compared to their recurrent parent. Furthermore, no yield penalty was observed in many of Cham5 derivatives; they had improved yield under unfavorable environments while maintaining the high yield potential from the recurrent parent (e.g., 142,026 and 142,074). It was found that a limited number of backcrosses can produce high yielding/stable germplasm while increasing diversity in a breeding pipeline. Comparing different stability approaches showed that some of them can be used interchangeably; others can be complementary to combine broad adaption with higher yield.


2007 ◽  
Vol 56 (1) ◽  
pp. 33-41 ◽  
Author(s):  
Shree P. Pandey ◽  
Sandeep Sharma ◽  
R. Chand ◽  
P. Shahi ◽  
A. K. Joshi

2020 ◽  
Vol 79 (04) ◽  
Author(s):  
Yashpal . ◽  
D. R. Rathod ◽  
Subhash Chandra ◽  
Anil Kumar ◽  
Raju Ratan Yadav ◽  
...  

Quantitative trait loci (QTL) mapping and analyses were conducted for yield and six yield-related traits in soybean using 184 inter-specific recombinant inbred lines (RILs) derived from a cross involving wild type (Glycine soja Sieb. and Zucc.) accession DC2008-1 and cultivated (Glycine max L. Merr.) variety DS9712. A Linkage map of 1639.55 cM length was constructed with 167 SSR markers (65.65% polymorphism) with an average marker interval of 9.82 cM. Using three years phenotypic data 34 QTLs were mapped for 7 traits using Inclusive Composite Interval Mapping approach. The number of QTLs mapped for a trait varied from year to year, however, QTLs for days-to-50% flowering (qDFF5), 100-seed weight (qHSW9-1, qHSW9-2 and qHSW19) and yield (qYLD17) were mapped consistently over the three years of testing. Identified QTLs were validated through single marker analysis in 92 germplasm lines. The study demonstrated the potential of wild type soybean to harness QTLs for yield-related traits. The identified QTLs could be utilized for genetic improvement of soybean through molecular breeding.


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