All BGRI Abstracts

Displaying 31 - 40 of 415 records | 4 of 42 pages

Disease resistance of primary hexaploid synthetic wheat and its crosses with bread wheat

BGRI 2018 Poster Abstract
Gular Gadimaliyeva Genetic Resources Institute, Azerbaijan
N. Aminov, A. Jahangirov, H. Hamidov, Aigul Abugalieva, Vladmir Shamanin, Alexey Morgunov

Hexaploid synthetics have become widely used in bread wheat improvement in recent years, enabling the introduction of specific traits as well as enhancing genetic diversity and development of valuable germplasm. This study demonstrated the difference between two groups of primary synthetics in terms of development rate, plant height, rust reactions, and productivity components. During 2015 and 2016, three groups of synthetics were studied in Azerbaijan (3 sites): Baku (0 masl) under irrigated conditions, Gobustan (850 masl) under dry rainfed conditions and Ujar (20 masl) under irrigated conditions with high salinity. Germplasm was also evaluated for diseases and agronomic traits in Omsk (Russia) in 2016.
All primary synthetics were resistant to leaf rust, several to stem rust, and few to stripe rust. Stripe rust occurred in all years at all sites, proving its importance as major wheat pathogen. Its severity reached intermediate levels in Baku in 2016 (33.7%) and in Gobustan in 2015 (26.8%), and epidemic level in Gobustan in 2016 (72.7%). Gobustan also experienced high levels of stem rust in 2016. These two diseases substantially reduced grain productivity in Gobustan in 2016, especially 1000 kernel weight (30.2 g) and grain weight per spike (1.17 g). . Superior genotypes from all three groups were identified that combine high expression of spike productivity traits and stress tolerance index. Five superior synthetics were selected from each of the three groups, based on grain weight per spike. Only four of these demonstrated resistance to stripe rust (entries 13, 15, 31, and 32). Japanese synthetics (group 3) were susceptible to stripe rust but all demonstrated resistance to stem rust. Synthetics from groups 1 and 3 were all resistant to leaf rust when tested under severe disease pressure in Omsk in 2016.

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First report of virulence to resistance genes Yrsp, Yr1 and Yr3 by wheat yellow rust pathogen (Puccinia striiformis f. sp. triti

BGRI 2018 Poster Abstract
Safarali Safavi Crop and Horticultural Science Research Department, Ardabil Agricultural and Natural Resources Research and Education Center, Ag
Farzad Afshari

Yellow (stripe) rust caused by Puccinia striiformis f. sp. tritici is the most devastating disease of bread wheat (Triticum aestivum) in the world. A wide range of virulent yellow rust pathotypes is evolving in different regions of the world causing the breakdown of widely utilized sources of resistance in wheat. Hence, the knowledge of virulence factors of pathogen and determining of effective resistance genes in the region will enable breeders to target those useful genes in their breeding programs. During cropping seasons of 2015-2016 and 2016-2017, virulence of the wheat yellow rust was investigated by planting differential cultivars and isogenic lines in a yellow rust trap nursery in Ardabil, northwest of Iran . Results showed stripe rust infections on some cultivars carrying Yr genes such as Yr1, Yr3, and Yrsp previously known to be resistant. The virulence spectrum of race population in Ardabil was identical to the Warrior race or its variants which is different from characterized races in Ardabil by carrying virulence combination for Yr1, Yr3, Yr17, Yr32, and YrSP and is avirulent on Yr8 and Yr27. Except for Yr8, Yr17 and Yr27, the common races in Ardabil are generally avirulent on Yr1, Yr3, and YrSP. This is the first report of race population in Ardabil (Iran) which is similar to the Warrior race or its variants.

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Identification of a new leaf rust resistance gene originated from Ae. speltoides via introgression to bread wheat

BGRI 2018 Poster Abstract
Jasline Deek Tel Aviv University
Assaf Distelfeld, Jacob Manisterski, Pnina Ben-Yehuda

Intensive breeding and replacement of traditional landraces by modern cultivars led to the narrowing of genetic variation in cultivated wheat. The most sustainable method for wheat improvement is utilization of genetic diversity from wheat wild relatives such as Aegilops speltoides that has a diversity of genes for resistance to leaf rust (LR). A high pairing-inducing Ae. speltoides strain collected from Israel was introgressed into T. turgidum subsp. durum var. landrace Nursi. The F1 plants were treated with colchicine to induce chromosome doubling. The resulting hexaploid plants were crossed to bread wheat cv. Beit-Lehem and F3 plants were backcrossed three times to bread wheat cv. Barnir. Each generation was selected for LR resistance to P. triticina isolate #1010 and five resistant wheat-Ae. speltoides introgression lines (ILs) designated DK1 to DK5 were selected. These Ae. speltoides ILs were genotyped using the 90K Infinium SNP assay and most of the polymorphic markers were mapped to chromosome 1B suggesting that the Ae. speltoides introgressions encompass most of this chromosome. To test if the newly identified gene is identical to Lr51, that was also introgressed from Ae. speltoides to chromosome 1B of bread wheat, the DK ILs were genotyped with the molecular marker AGA7 that was shown to be linked to Lr51. The Ae. speltoides AGA7 allele was absent in the DK ILs suggesting that these genotypes are not carrying the Lr51 introgression. Moreover, we performed an allelism test. Spring wheat cv. Kern harboring resistance gene Lr51 was crossed with DK2 and an F2 segregation ratio of 15R:1S was obtained, indicating that the resistance was conditioned by two independent dominant genes. Overall, our results suggest that DK2 carries a new leaf rust resistance gene from Ae. speltoides and this gene has potential for wheat improvement.

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Impact of different levels of stem, stripe and leaf rust severity on two grain yield components of wheat in Egypt

BGRI 2018 Poster Abstract
Mohammed Abou-Zeid Wheat Diseases Department Plant Pathology research Institute, Agriculture Research Center.

Improvement of wheat (Triticum aestivum L.) is a major goal of plant breeders and pathologists to ensure food security and self sufficiency. Relationship between different levels of stem, stripe and leaf rust severity on the two grain yield components (1000-kernel weight and plot yield) were studied during 2015/2016 and 2016/2017 seasons at Sids Agricultural Research Station. Different epiphytotic levels of stem, stripe and leaf rust were created using spreader artificial inoculation and spraying the fungicide Sumi-eight. To create different rust severity, one, two, and three sprays were applied at 7 day intervals. Protected control treatment was obtained by spraying the fungicide four times. Correlation coefficient (R<sup>2</sup>) analysis depicted that positive correlation was found between different rust severity levels and yield loss. In 2015/2016 growing season, which stem rust started early, disease severity (%) reached its relatively high percentage (80%) with the highest loss (%) in both 1000 kernel weight (36.3%) and plot weight (37.82%). The effect of stripe rust infection on yield components was lower than those of stem rust and lowest in leaf rust. On the other hand, the lowest loss was observed with 10% of stem, stripe and leaf rust which sprayed three times. During 2016/2017 stripe rust infection caused the highest loss (%) in yield components, under the highest level 80% of severity, on the other hand leaf rust showed low level of loss (%) Compared with the stripe and stem rust.

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Enhancing crop genetic diversity using crop wild relatives (CWR)

BGRI 2018 Poster Abstract
Chetan Patokar International Center for Agriculture Research in Dry Areas (ICARDA)
ahmad amri, El-Haddoury Jamal

Constant climatic change and rapid evolution of diseases and pests have created challenges for plant breeders to find novel sources of resistance within cultivated gene pool. However wild (alien) relatives of crops still carries many promising resistance genes to biotic and abiotic stresses. Plant breeders around the world have successfully attempted to recover some of the beneficial genetic diversity lost (or never included) during the domestication and crop improvement process by crossing cultivated varieties with wild species to introgressed many valuable genes into crops like wheat and barley. This pre-breeding attempt to regain the genetic diversity of crops based on crop wild relatives (CWR) had been started at ICARDA 1994. Furthermore, The Global Crop Diversity Trust (GCDT) recently provided a grant to ICARDA within the Crop Wild Relatives (CWR) project to strengthen the research on use of genetic resources in pre-breeding of barley and grass pea. The pre-breeding activity in barley is focused on transferring genes of resistance to complex diseases and pests (scald, spot blotch and barley gall midge), improving tolerance to drought, heat and salinity, and enhancing the nutritional value through improving Iron and Zinc concentrations and amylases activity. Crosses were made between wild barely H. Vulgare X cultivated barley H. Vulgare subsp. H. spontaneum. The main objective of pre-breeding in Grasspea is transferring genes of low or no ?-ODAP from crossable species L. cicera and L. amphicarpus, L. tingitanus, L. aphaca, L. odoratus, L. sphaericus, L. nissolia, and L. aureus. Interspecific crosses were made between L. sativus x L.cicera followed by embryo rescue. Currently all the pre-breeding lines with targeted traits are under screening against the respective selection pressures using precision phenotyping..

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Mining of hulled wheat species for yield gain in bread wheat (Triticum aestivum L.)

BGRI 2018 Poster Abstract
Vikas Venu Kumaran ICAR-Indian Agricultural Research Institute, Regional Station, Wellington, The Nilgiris, Tamilnadu, India
SIVASAMY,MURUGASAMY, JAYAPRAKASH, PARAMASIVAM, RAJESH KUMAR, MEENA, , , , , , , , , , , , , , , , , , , , , , , ,

Emmer wheat (Triticum dicoccum L.), tetraploid species (AABB) and spelt wheat (Triticum spelta L.), hexaploid species (AABBDD) are old world hulled wheat species cultivated centuries ago in different parts of the world. These species were later replaced by higher yielding bread and durum wheat in the last centuries. Grain yield is influenced by grain number per unit area and grain size which correlates positively with grain weight. Increasing the grain number was extensively and intensively explored in the past 100 years of wheat breeding which has nearly reached to saturation and leaves little room for further yield increase due to grain number?grain size trade off. Grain size/grain weight is believed to be major driving force for further improvement of wheat yield. Both the species have been characterised with larger grain size and higher grain weight; therefore an ideal source to improve the grain size/grain weight while maintaining the grain number per spike in the cultivated bread wheat. A total of 25 accessions each of emmer and spelt wheat with good grain size and weight were crossed with 5 elite bread wheat lines. In the F2 generation, recombinant lines with good grain size, higher grain weight and grains number were further backcrossed with bread wheat. Stable lines with free threshing were obtained at BC4F4 generations and were analysed for quality. Thousand grain weight (TGW) and harvest index (HI) ranged from 46-55g and 0.47-0.58 in stable lines respectively. Stable lines yielded 16-21% than the high yielding check while number of grains per spike was maintained as that of check. Stable lines involving spelt crosses have higher grain size, TGW and HI than emmer wheat crosses. Stable lines could be released directly as cultivar or else used as one of the parents in the wheat improvement programme.

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Genetic variation and differentiation in global populations of the wheat leaf rust fungus, Puccinia triticina.

BGRI 2018 Poster Abstract
James Kolmer USDA-ARS Cereal Disease Laboratory
Maria Ordonez, Silvia German, Kun Xiao, Amy Fox, Maricelis Acevedo

The leaf rust pathogen, Puccinia triticina is widespread across all major wheat growing regions worldwide. Collections of P. triticina were obtained from common and durum wheat in North America, South America, Europe, South Africa, the Middle East, East Africa, Russia, Central Asia, China, Pakistan and New Zealand in order to determine the genetic diversity within each region and genetic relationship between regions. A total of 831 single uredinial isolates were characterized for virulence to isogenic lines of Thatcher wheat and for molecular genotype at 23 SSR loci. The isolates in East Africa and Europe were the most diverse for the average number of effective alleles per locus, while the populations in Russia and North America were the least diverse. The isolates in Europe and South America had the highest number of multilocus genotypes of 81 and 75, respectively, and were the most diverse for Shannon's genotypic diversity. All populations had significantly higher levels of Ho compared to He at individual SSR loci, and had highly significant values of Ia and rd which indicated clonal reproduction. Europe had the highest number of distinct SSR genotype groups with eight, and Russia had only two SSR groups. The populations in North America and South America; Russia and Central Asia; the Middle East and East Africa; were closely related for SSR genotype based on Nei's genetic distance. Based on k means clustering and DAPC of SSR genotypes, isolates virulent to durum wheat were placed into a single separate group, and isolates virulent to common wheat were placed into five other groups. Twenty-seven SSR genotypes were found in different continental regions. Isolates with identical or highly related SSR genotypes also had identical or similar virulence, which indicated historical and current migration of P. triticina worldwide.

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Identification and Analysis of RNA Editing Sites in the Chloroplast Transcripts of Aegilops tauschii L.

BGRI 2018 Poster Abstract
Mengxing Wang State Key Laboratory of Crop Stress Biology in Arid Areas, Northwest A&F University, Yangling 712100, Shaanxi, China
Hui,Liu, Guangwei, Xing, Xiaojun, Nie, Song, Weining, , , , , , , , , , , , , , , , , , , , , ,

RNA editing is an important way to convert cytidine (C) to uridine (U) at specific sites within RNA molecules at a post-transcriptional level in the chloroplasts of higher plants. Although it has been systematically studied in many plants, little is known about RNA editing in the wheat D genome donor Aegilops tauschii L. Here, we investigated the chloroplast RNA editing of Ae. tauschii and compared it with other wheat relatives to trace the evolution of wheat. Through bioinformatics prediction, a total of 34 C-to-U editing sites were identified, 17 of which were validated using RT-PCR product sequencing. Furthermore, 60 sites were found by the RNA-Seq read mapping approach, 24 of which agreed with the prediction and six were validated experimentally. The editing sites were biased toward tCn or nCa trinucleotides and 50-pyrimidines, which were consistent with the flanking bases of editing sites of other seed plants. Furthermore, the editing events could result in the alteration of the secondary structures and topologies of the corresponding proteins, suggesting that RNA editing might impact the function of target genes. Finally, comparative analysis found some evolutionarily conserved editing sites in wheat and two species-specific sites were also obtained. This study is the first to report on RNA editing in Aegilops tauschii L, which not only sheds light on the evolution of wheat from the point of view of RNA editing, but also lays a foundation for further studies to identify the mechanisms of C-to-U alterations.

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Response of durum wheat genotypes to rust in preliminary and regular yield trials

BGRI 2018 Poster Abstract
Iqra Ghafoor Wheat Research Institute, Ayub Agricultural Rsearch Institute Faisalabad
Amna Kanwal, Mehwish Makhdoom, Javed Ahmed, Makhdoom Hussain

Wheat is the most important cereal crop in Pakistan because it contributes major portions of daily calorie intake. Rust is an increasing threat to wheat production and ultimately food security in Asian countries. The purpose of the present study is to identify the suitable wheat lines that could significantly resist rust pathogen without compromising yield. 60 durum wheat lines, entered in preliminary and regular yield trials, were tested for various morphological and physiological traits along with adult plant disease reaction under natural rust infestation. Results indicated that there was higher incidence of yellow rust as compared to leaf rust as ten genotypes were susceptible to leaf rust. Whereas seven lines were moderately susceptible, 14 were moderately resistant and two were completely susceptible to yellow rust. These findings suggested that future breeding program should be directed towards the developments of resistant cultivars that could resist variable strains of rust pathogen under changing climatic conditions.

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Stripe rust resistance in Indian wheat cultivars and advance lines

BGRI 2018 Poster Abstract
Mahender Singh Saharan ICAR-IARI, New Delhi
Sudheer Kumar, Subhash Chandar Bhardwaj, Om Prakash Gangwar, Vaibhav Kumar Singh, Mukesh Kumar Pandey, Jaspal Kaur, Ashwani Kumar Basandrai, Deepshikha, Pradeep Singh Shekhawat, R.K. Devlash, V.K. Rathee

In India, wheat crop is a major contributor to the agricultural economy of India, occupying 30.7 mha area with 98.38 mt production. Stripe or yellow rust is a constraint to wheat production on about 12.0 m ha in the Northern Hills and North Western region of India. Varieties resistant at the time of release become susceptible usually within a few years due to new pathogen races. The present study conducted in 2015-16 was undertaken to identify stripe rust resistant genotypes among a set of 146 advanced breeding lines and popular cultivars. All genotypes were planted in two replications in northern India at ten locations viz., Karnal, Hisar (Haryana), Ludhiana, Gurdaspur (Punjab), Malan, Bajoura, Dhaulakuan (Himachal Pradesh), Pantnagar (Uttarakhand), Durgapura (Rajasthan), Jammu (J & K) and Delhi. After every 20 genotypes, infector (susceptible cultivar to both pathotypes) was planted. All genotypes were inoculated with mixture of prevalent Pst races 78S84 (Yr 27 virulence) and 46S119 (Yr 9 virulence) at Karnal. Out of 58 released cultivars grown in different zones of the country, fifteen lines (HS 507, DBW 90, HD 3086, WH 1080, WH 1124, WH 1142, HD 4728, HI 8498, HI 8737, MPO 1215 (D), NIDW 295 (d), UAS 428 (D), UAS 446 (D), DBW 71, KRL 210) showed stripe rust ACI < 10.00 (average coefficient of infection). But among advance 88 wheat lines, there was good level of resistance in 50 lines (ACI <10.00). Lines having AUDPC values <20% of those of the susceptible checks (maximum AUDPC value 2500 on susceptible check) were considered to be slow rusters. In present study, some of the wheat varieties (DBW 93, HS 490, PBW 723, PBW 644, VL 829, VL 892, WH 1105, WR 544 ) grown at present in northern India were identified as slow ruster lines. The information generated can be utilized in improving the stripe rust resistance of popular cultivars.

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