Institute of Agricultural Sciences, Banaras Hindu University, India-221005
Punam Singh,Yadav, Naveen Kumar, Umesh Chandra, Dubey, Ramesh Chand, Sundeep Kumar, Arun Kumar Joshi
Four leaf rust adult plant resistance genes (Lr34, Lr46, Lr67 and Lr68) are known to be associated with leaf tip necrosis (LTN). LTN caused by these genes is different from each other at phenotypic level. LTN associated with APR genes Lr34, Lr46 and Lr67 has been designated as Ltn1, Ltn2 and Ltn3. Seventy-seven CIMMYT genotypes were selected to find out the association between genotypic and phenotypic variability for LTN and its association with yield traits; 1000 grain weight, grain yield, leaf area and percentage of leaf tip necrosis in the flag leaf of main tiller. All the genotypes were screened for the presence of 3 APR genes with linked markers, csLV34 for Lr34; Xwmc44 and Xgwm259 for Lr46 and Xcfd71 for Lr67. The genotypes were grouped into 5 classes; only Lr34, only Lr46, only Lr67, Lr34+L46+Lr67 and genotypes lacking all three genes. Molecular analysis revealed that 7 genotype with Lr34 only, 6 with Lr46 only, 7 with Lr67 only, 13 with all the 3 genes, and 28 without any Lr gene. Phenotypic data of LTN percentage was compared and it was noted that maximum LTN % was observed for Lr67 (7.811%) followed by Lr46 (7.348%) and Lr34 (6.47%). Surprisingly, presence of all three genes reduced the LTN% (4.7055%) as compared with absence of all three genes (6.011%). It was also observed that the three genes simultaneously reduced 1000 grain weight and plot yield. All three genes increased leaf area highly significantly both when they are alone or together (34.7 to 44.7 cm2) in comparison to those genotypes (24.7 cm2) which lacks these Lr genes and also reduced 1000-grain weight and plot yield but non-significantly.
The Ohio State University
Nelly Arguello-Blanco, Mao Huang
Genomic selection facilitates rapid cycling through a breeding cycle by eliminating the need to phenotype prior to selecting superior parents and crossing among them. In winter wheat we can now complete a cycle of GS in about 12 months and two greenhouse seasons. Season consists of planting F1s from the previous cycle and selfing to obtain F2 seed. The second season involves planting and genotyping the F2s, predicting their value with GS, selecting and crossing the best, and harvesting the F1 seed. Our breeding program has completed five cycles of GS in one population primarily for grain yield, over the past five years. We have completed three cycles of GS for resistance to Fusarium Head Blight in a second population. Genotyping was done using genotyping-by-sequencing. This provides an opportunity to assess the changes in the population that have occurred as a result of this rapid cycling. These include 1) changes in genomic estimated breeding values for grain yield and FHB resistance, 2) effect of selection and drift on allele frequencies including fixation, 3) effect of selection on diversity and genetic relationships, and 4) changes in linkage disequilibrium. We are conducting these analyses and will present the results.
Muhammad,Noor, Makhdoom, Hussain, Majid, Nadeem, Monsif, ur Rehman, Jesse, Poland, Ravi, Prakash Singh, Matthew, Reynolds,, , , , , , , , , , , , , , , ,
Drought and heat along with rusts are the most common biotic and abiotic stresses that affect growth, development and yield of wheat crop in Pakistan. CIMMYT in partnership with Wheat Research Institute Faisalabad (WRI-Fsd), USDA, and Kansas State University initiated an effort to develop heat tolerant, high yielding, and farmer-accepted rusts resistant wheat varieties for Pakistan. A set of 1656 wheat lines received in the form of EPCBW and SABWGPYT nurseries were tested in 2013-14 and 2014-15 wheat season, respectively. Testing of the materials at (WRI-Fsd), Pakistan under normal and late planting conditions resulted in the selection of 55 lines with higher grain yield and resistant to both leaf (LR) and yellow (YR) rusts. Among these lines, the line no. 1027 produced maximum yield (5.78 ton/ha) under normal and line no. 5030 produced maximum yield (3.38t/ha) under late planting conditions with resistance to both LR and YR. Further evaluation of the selected 55 lines as HYT-60 in 2015-16 showed the average grain yield ranged from 4.98 to 2.51 ton/ha under normal and 1.74 to 0.73 t/ha under late planting. Three lines HYT-60-57, HYT-60-7 and HYT-60-5 were included in the first year advanced yield trials to test for their potential as commercial cultivars while another seventeen lines were distributed as HYT-20 to six national wheat breeding programs for yield testing at key location which will enable national partners to combine yield potential with resistance to biotic and abiotic stresses.
Wheat Disease Research Department, Plant Pathology Research Institute, Agricultural Research Center, Giza, Egypt
Stripe rust (Puccinia striiformis f. sp tritici) (Pst) infected wheat samples collected from three Egyptian Governorates (Alexandria, Beheira and Kafr-El Sheikh) were processed for race analysis to determine the race identity among the current populations of the stripe rust fungus. Single uredinial isolates were inoculated to a core set of the 17 World/European differential hosts along with wheat lines with Yr17, Yr25, Yr32. Based on virulence phenotyping, the data revealed that the current populations of Pst belong to three races: Triticale aggressive (virulent to Yr2, Yr6, Yr7, Yr8, Yr10); PstS3 (virulent to Yr2, Yr6, Yr7, Yr8, Yr25); and PstS2 (virulent to Yr2, Yr6, Yr7, Yr8, Yr9, Yr25, Yr27). No collections were found with the Warrior race, that has virulence to Yr1, Yr2, Yr3, Yr4, Yr6, Yr7, Yr9, Yr17, Yr25, Yr32, YrSp).
The University of Jordan
Ayed Al Abdallat, Monther Tahat
Studies on whet stem rust (WSR) in Jordan are considered to be old. There was only one study conducted in the late 1980's by Abu-Blan and Duwayri (1989) to evaluate the infection of wheat cultivars with black stem rust disease (Puccinia graminis f. sp. tritici). Recently, reports of stem rust were published in Israel and Lebanon in 2010 and first report of Ug99 was reported in Egypt in 2014. The objectives of our research are to: (i) survey wheat growing areas for WSR in Jordan during the years 2017-2020, (ii) identification of WSR races isolated from Jordan morphologically and molecularly, (iii) analyze rust populations in terms of their response to known differential sets, pathotype distribution and diversity, (iv) screening the response of Jordanian wheat germplasm to the identified WSR strains, and (vi) study the population diversity of WSR races using RT-PCR and SNP genotyping. In 2017 a total of 270 fields of wheat and barley in the wheat and barley growing areas in Jordan were surveyed from March-May. The survey covered northern, middle, and southern parts of Jordan (arid and semi-arid regions). Altitude, longitude, and latitude data was recorded. Only few WSR pustules (n=4) were collected because the environmental conditions were not suitable for the disease to develop. On the other hand, wheat stripe rust was very common in the wheat growing areas mainly at the southern parts of the country. Other fungal plant pathogens were also reported including smuts, spots, blotches, powdery mildew, crown rot, fusarium head blight, and flag smut.
Institute of Molecular Biology and Biotechnology, Azerbaijan National Academy of Sciences
Shahriyar Sadigov, Alamdar Mammadov, Irada Huseynova
Rust of cereals are considered to be an important disease in many countries, including Azerbaijan. One of these is stem rust caused by Puccinia graminis f. sp. tritici (Pgt). Extensive research on the identification of wheat stem rust resistance genes and effectiveness of these genes in various geographical regions have been conducted. Genetic resistance is one of the most effective ways for controlling stem rust. Sixty-nine stem rust resistance genes (including 45 identified Sr genes and 24 genes with temporary designations) are registered in the Komugi Wheat Genetics Resource Database. It is important to use proper combinations of resistance genes in developing lasting resistance wheat. The main purpose of the study was to identify lines caring Sr11, Sr26 and Sr31 genes, which are effective to the predominant Pgt races in Azerbaijan. Durum and bread wheat genotypes differing in their disease resistance, productivity and other physiological traits were chosen from the wheat gene bank of the Research Institute of Crop Husbandry (Baku, Azerbaijan) for analysis. DNA extraction was carried out according to standard CTAB protocol. RT-PCR performed using KASP markers (KASP_6BL_BS0074288_51 and KASp_6BL_Tdurum contig55744_822) identified nine durum genotypes (out of 34 genotypes) and seven wheat genotypes (out of ten genotypes), caring Sr11. Using the dominant STS marker (Sr26#43) a diagnostic 207 bp amplicon for Sr26 gene, was observed in 11 of the 42 wheat genotypes tested. In eight of the 42 wheat genotypes tested, the diagnostic 1,110 bp amplicon was observed using the Lr26-Sr31-Yr9 locus specific marker iag95, characteristic of Sr31 gene located at 1BL.1RS translocation. For the first time, wheat germplasm in Azerbaijan was analyzed using KASP genotyping technology and genetic resources, and resulted in the identification of wheat lines with effective resistant to Puccinia graminis f. sp. tritici race TKTTF.
National Agronomic Research Institute of Algeria
Among the many biotic constraints to wheat production in Algeria, rusts and in particular yellow rust (Puccinia striiformis), are among the most prevalent diseases that occur mostly all over the northern part of the country. Yellow rust has become now sporadic due to the exploitation of effective resistant genes in different forms and combinations (from CIMMYT and ICARDA). Earlier, durable resistance was probably due to many genes, such Yr18, Yr9, Yr27 and Yr1.
Yellow rust appeared as epidemic in 2004, over 600 000 ha of bread wheat ; severity exceeded 70%. Yields from affected fields of Hidhab a susceptible variety did not exceed 5.2 q/ha, while resistant cultivars yielded up to 48 q/ha. Monitoring of the pathogen virulence factors and their changes provides basic information for the development of an early warning system. This experiment was carried out in 5 Eastern Algeria locations. 30 lines of a standard set of yellow rust and 14 near-isogenic lines from ICARDA were sown in 2-m rows in 2014 and 2015. According to the results, virulence on Heines Kolben (Yr2), Kalyansona (Yr2), Lee (Yr7), Avocet R (YrA), Federation*4/Kavkaz (Yr9), Yr6/6*Avocet ?S?, Yr7/6*Avocet ?S?, Yr9/6*Avocet "S", Yr17/6*Avocet "S", TP1295 (Yr25) and YrSU was common during those two seasons. The frequency of virulence on plants with Yr2, Yr6, Yr7, Yr9 or YrA and Yr27 was up to 80%. No virulence was observed on plants with Yr1, Yr3, Yr4, Yr5, Yr8, Yr10, Yr15 and Yr18 genes. This material was extensively used in our breeding programs and several new cultivars are in the on farm trials where a participatory selection approach is used. All resistant and performing new varieties are being spread for replacement of most old susceptible ones.
Wheat Dis. Res. Dept., Plant Pathol. Res. Inst., A.R.C., Sakha, Egypt
Les John Szabo
Stem rust, caused by Puccinia graminis f. sp. tritici (Pgt), is one of the most serious disease of wheat worldwide. The discovery of new Pgt races in Africa, Ug99 and its variants, brings a new threat to global wheat production. In this study, 50 single pustule stem rust samples, were collected during 2015-2016 from the International Stem rust Trap Nursery (ISRTN) and commercial wheat fields in Sakha, the most important wheat growing region in Egypt. SNP-genotyping was carried out at USDA-ARS Cereal Disease Laboratory. Infection and genotype data confirmed that none of these samples belonged to the Pgt Ug99 race group. Forty-five samples were successfully genotyped consisting of 12 multi-locus genotypes (MLGs). The majority (86.7%) of the samples belonged to three clades: 10 samples, clade III-B (MLG.04, race TTRTF) collected from Misr 3, Sakha 95 and Sids 14 wheat lines; 12 samples, clade IV-A.2 (MLG.06, race TKTTF) collected from Sr 5, Sr6, Sr7a, Sr7b, Sr8b, Sr9a, Sr9e, Sr10, Sr11, Sr15, Sr16 and Sr17 wheat lines; 17 samples, clade IV-E.2 (MLG.11, race TKKTF) from Sr13, Sr14, Sr19, SrMcN, Sr24, Misr 1, Misr 2, Sakha95 and Sids 12 wheat lines. Pgt samples belonging to clades IV-A.2 and IV-E.2 have been observed from Europe to the Middle East, and samples from clade III-B from the southern Caucasus Mountains, Middle East to northeast Africa. The remaining six samples collected from Sr12, Sr18, Sr20, Sr21, Sr22 and Sr25 wheat lines represent two new genotypes (MLG.14 and MLG.17) that have not been assigned to clades. MLG.14 was also observed in samples from Azerbaijan, Iraq and Eritrea. In contrast, this represents the first detection of MLG.17. These results suggest continued variability of the Pgt population in Egypt therefore, emphasizing the importance regularly monitoring to timely identify new races, and utilize this information in screening and identification of effective sources of resistance.
Department of Botany, Faculty of Biology, Government College Murree, Pakistan
Barkat Ali, Muhammad Fayyaz, Atiq ur Reman Rattu, Abdul Samad Mumtaz, Muhammad Imtiaz
The new arrival of wheat rust pathotypes through migration during wheat cropping season requires regular monitoring to secure wheat production. In the present study, we collected leaf rust (Puccinia triticina Eriks.) infected wheat leaves from three major wheat growing provinces of Pakistan in the year 2014 to assess the haplotype diversity of P. triticina (Pt) isolates. The rDNA ITS sequence data of collected isolates was used in NCBI BLAST analysis. The blast hits showed best matches with Pt accessions EU014050 (Iran), JN120331 (Iran), JX533577 (Iran), AY956549 (Iran), DQ417412 (Czech Republic), DQ417418 (Israel), DQ417413 (Slovakia) and AF511083 (Louisiana). However, in cluster analysis, the Pakistani isolates showed strong bootstrap support with only Iranian and Indian (races 77-5 & 104-4) accessions that indicated eastward migratory mode of Pt pathotypes in Pakistan through westerly wind patterns. The predominant genotype DQ417412 (similar in alignment with AY956549 from Iran) overcome the resistance of top Pakistan mega varieties Seher06, Inqilab91, Kiran95, SKD1, TJ83 and NIFA-Batoor. Hence, the ITS based information remains a rapid molecular tool for pathogen surveillance across countries and continents.
The University of Agriculture, Peshawar, Pakistan
Muhammad Khan, Muhammad Ismail, Sher Nawab, Abdullah Jalal, Muhammad Imtiaz, Sajid Ali
Rust disease response is used to assess the resistance status of breeding lines, which is required to be tested across location and complemented with molecular markers. The current study was designed to characterize yellow rust resistance in 29 introduced advanced CIMMYT wheat lines along with three check varieties across three contrasting wheat growing regions (Peshawar, Mansehra and Lakki-Marwat) during wheat season 2015-16. A high disease pressure was observed across all three locations as favorable cold and wet climatic conditions prevailed during 2015-16. The maximum disease was recorded at Mansehra (up to 90%) followed by Peshawar (up to 50%) and Lakki-Marwat (up to 45%). There was a significant variability amongst the tested wheat lines for yellow rust severity and in yield potential. Among the advanced lines, W-SA-104, W-SA-115 and W-SA-118 had better grain and biological yield. Based on disease and yield parameters, cluster analysis of 29 wheat lines along with three checks grouped wheat lines into four clusters. None of these wheat lines showed resistance at every location (Average coefficient of infection "ACI" = 0). The maximum co-efficient of infection (55) was recorded at Mansehra whereas the minimum (0) was recorded at Peshawar and Lakki-Marwat. Twenty-six of these wheat lines were identified to possess partial resistance to yellow rust (with ACI < 20). Genotyping for the presence of resistance gene markers STS-7 (linked with Yr5), SC-Y15 (linked with Yr17) and Xwmc-44 (linked with Yr29) revealed the highest frequency of Yr17 (90.60%), followed by Yr29 (87.5%) and Yr5 (50%). The three resistant genes together were present only in 15 wheat lines (46.87%). Our results thus revealed the presence of variation in resistance response based on both field testing and molecular markers which could be utilized in wheat breeding to develop better resistance varieties to be exploited at field level.