University of Hohenheim, Germany
Afrem,Issa, Helim, Youssef, Nawzad, Suleiman, Abdul Rahman, Issa, , , , , , , , , , , , , , , , , , , , , ,
Wheat is grown in Syria during the November-December. Wheat is exposed to many strains that negatively affect its productivity especially rust diseases, which was reported on wheat in Syria for many years and the most severe in 2010, Therefore, we studied the effect of planting dates on the severity and development of yellow rust disease. Where the field trials of the 2010-2011 season were carried out at the two locations in northeastern of Syria: Al-Qamishli Research Center and Yanbouh Research Station in Al-Malekia. By cultivating the susceptible bread wheat Cham 8, where six dates were planted starting from 02.10. 2010, a difference of 15 days. The results showed there was a difference in the severity of the yellow rust disease according to the dates of cultivation and thus the stages of growth in the plant and this was evident in the Yanbouh location where the onset of the onset of injury on 08.04.2011 in the all dates and developed the infection to 40S degrees and 30%. Also, on the 24. 04. 2011, the infection was recorded at the Qamishli location only on the third and fourth dates. The disease did not develop more than 10S and 10% due to climatic conditions due to rain and high temperature during the season. The results showed a positive correlation between the evolution of the disease and vegetative growth of plants, where the growth of plants was more active at the site of Yanbouh, especially in the second, third and fourth dates in the development of infection on plants in the rest of the dates because of weak and slow growth of plants.
Research Center of Agricultural and Development in Northwest Semi-arid regions of Tunisia
Afef,OTHMANI, Olfa, SLAMA-AYED, Hajer, SLIM-AMARA, Mongi, BEN YOUNES, , , , , , , , , , , , , , , , , , , , , ,
Eleven durum wheat (Triticum durum Desf.) genotypes were screened to select for drought-tolerance under in vitro immature embryos culture. Drought stress is induced by using five PEG concentrations (0, 200, 270, 295 and 310 g/l of PEG 6000). Results showed, for all studied traits, significant differences among PEG treatments and genotypes. In fact, increasing PEG concentration decreases relative growth rate, callus water content, relative water content, in vitro tolerance and relative tolerance. Biplot analysis indicated that the first two PCs (principal components 1 and 2) explain 70.5 % and showed that Karim, Mahmoudi and Om Rabiaa are respectively the most drought tolerant varieties tested, however, Ben Bechir, Maghrbi and Nasr were the most sensitive.
Filippo,Bassi, Rodomiro, Ortiz, Ibrahima, Ndoye, AbdelKarim, Filali-Maltouf, Bouchra, Belkadi, Miloudi, Nachit, Michel, Baum, Hafssa, Kabbaj, Habibou, Gueye, Madiama, Cisse, , , , , , , , , ,
Wheat is a major food crop in West Africa, but its production is significantly affected by severe heat. Unfortunately, these types of high temperatures are also becoming frequent in other regions where wheat is commonly grown. In an attempt to improve durum wheat tolerance to heat, a collection of 287 elite breeding lines, including several from both ICARDA and CIMMYT, was assessed for response to heat stress in two irrigated sites along the Senegal River: Fanaye, Senegal and Kaedi, Mauritania during 2014-2015, and 2015-2016 winter seasons. The maximum recorded grain yield was 5t ha-1, which was achieved after just 90 days from sowing to harvesting. Phenological traits (heading, maturity and grain filling period) and yield components (1000-kernel weight, spike density and biomass) had also large phenotypic variation and a significant effect on grain yield performance. This panel was genotyped by 35K Axiom to generate 8,173 polymorphic SNPs. Genomic scans identified a total of 34 significant association between single nucleotide polymorphisms (SNPs) and traits across the four environments, including 15 related to phenological adaptation, 12 controlling grain yield components, and seven linked to grain yield per se. The identification of these genomic regions can now be used to design targeted crosses to pyramid heat tolerance quantitative trait loci (QTL), while the SNPs underlying these QTL can be deployed to accelerate selection process facilitated by DNA-aided breeding.
Turkey-ICARDA Regional Cereal Rust Research Center (RCRRC), ICARDA, Menemen, Izmir, Turkey
Muhammad Massub Tehseen, Ezgi Kurtulus, Maha Al Ahmed, Ahmed Amri, Mariana Yazbek, Ali Shehadeh
In 2016 the bread wheat (BW) and durum wheat (DW) landrace accessions were evaluated against PstS2 and in 2017 against a mixture of PstS2 and warrior race in field inoculations at Izmir precision stripe rust phenotyping platform. Inoculation was carried out three times during seedling, tillering and booting stages using mixture of fresh spore and talcum powder. Adult-plant responses of tested accessions were recorded according to 0-9 scale once the flag leaf of the susceptible cultivar became fully susceptible. During 2016, out of 3319 BW accessions, 1135 (36%), 871 (28%) and 1133 (36%) were found resistant (1-3 scale), moderately resistant (4-6), and susceptible (7-9) to PstS2, respectively. Amongst the resistant accessions in 2016, 1043 (33%) remained resistant while 786 (25%) showed moderate resistant and 1310 (42%) became susceptible. In 2017, 43% of moderately resistant accessions showed susceptibility to warrior race and 57% remained resistant to moderately resistant. Within the susceptible accessions to PstS2 race in 2016, 22% showed resistance to the warrior race and the remaining were susceptible. In case of DW in 2016, 76% (553) of the accessions were resistant to PstS2, 23% (163) were moderately resistant and only 1% (7) were found susceptible. In 2017, 329 (46%) of the resistant accessions were found resistant, whereas 289 (40%) and 105 (15%) showed moderately resistance and susceptible reaction to Warrior race, respectively. The present data indicated that BW landraces were generally more susceptible to stripe rust than DWs. Susceptibility of both BW and DW accessions to Warrior race indicated that most likely some of the uncharacterized resistance genes which conferred resistance to PstS2 were ineffective against the warrior race. Sources of resistance to both races were identified in both BW and DW. Genetic architecture of identified sources of resistance in present study requires further investigations.
Wheat Research Institute, Ayub Agricultural Research Institute,Faisalabad,Pakistan
Mehvish,Makhdoom, Javed, Ahmad, Makhdoom, Hussain, Iqra, Ghafoor, , , , , , , , , , , , , , , , , , , , , ,
Wheat crop is facing immense losses each year owing to climate change, eventually being major threat to global food security. So, the objective of the present study was to screening of advance lines under drought and heat stress conditions. In following study, 30 advance lines of wheat along with four checks(Faislabad-08, Millat-11, Galaxy-13 and ujala16) with three treatments (heat, drought, normal) were tested for different morphological (days to heading, plant height, days to maturity, biomass,1000 grain weight and grain yield) and physiological (canopy temperature at vegetative & reproductive stage, NDVI vegetative & reproductive), parameters. Biplot analysis depicted that V2, V3, V8, V14, V19, V25, and V30 showed the highest OP vector for grain yield in drought environment. Whereas, under heat conditions, V3, V4, V5, V10, V11, and V12 displayed their maximum longest vector for grain yield. Correlation analysis depicted that grain yield had non-significant correlation with canopy temperature (vegetative stage), normalized difference vegetation index (vegetative stage) canopy temperature (reproductive stage), plant height, days to heading and days to maturity under heat stress environment, while it had significant association with biomass and thousand grain weight. Under drought environment, grain yield had positive and significant correlation with biomass while on the other hand it had negative but significant association with normalized difference vegetation index (reproductive stage) and canopy temperature (reproductive stage). Best performing lines could be efficiently exploited in research programs to evade the perilous impact of climate change.
University of the Free State
Gerrie Booysen, Willem Boshoff, Jozua Joubert
Urediniospores of rust fungi can be applied to cereal plants in several ways. Depending on the objective and available infrastructure, plants can be inoculated with a suspension of spores in either water, light mineral oil (e.g. Soltrol 130®) or engineered fluid (e.g. Novec 7100®). Alternatively, dry spores can be allowed to settle on plant surfaces by dusting or directly applied with a spatula or small brush. Several rust laboratories employ a system where a spore-oil suspension, contained in a gelatin capsule, is sprayed onto seedling leaves by means of a dedicated atomizer connected to an air pressure source. Although this approach is easy to use and highly efficient, the devices are not commercially available in South Africa. Locally, these inoculation appliances need to be manufactured by a conventional milling process that requires a specialized workshop and skilled personnel. This subtractive process is labour intensive and greatly prohibitive in terms of costs. Using a process called Additive Manufacturing (AM), also known as "3D printing", the body of an inoculator was digitally designed and then laser sintered in nylon. Loose powder was removed from flow channels by compressed air. A copper tube fitted afterwards connected the nylon body with the spore suspension in the capsule. Replicated inoculation tests of wheat seedlings with urediniospore bulks or single pustule collections of Puccinia triticina and P. graminis f. sp. tritici resulted in consistent levels of rust severity and infection frequency. Cleaning of inoculators in acetone for 1 min followed by a 1 h heat treatment at 60°C produced no contaminant infection in follow-up tests. The design has been registered in South Africa, the USA and Europe.
Plant Pathology Research Institute
,, , , , , , , , , , , , , , , , , , , , , , , , , , , ,
Leaf rust resistance genes Lr9 and Lr19 were previously highly effective against the most predominant races of Puccinia triticina in Egypt. In 2015/2016 growing season, susceptible field reaction was recorded on these two genes where rust severity reached about 40S for Lr9 and 5S for Lr19 under Egyptian field conditions at four locations i.e. El-Behira, El-Minufiya, El-Qalubiya and El-Fayom governorates. Eight leaf rust field samples were collected from these governorates (four from each of Lr9 and Lr19). Forty single isolates were derived from the collected samples of Lr9 and Lr19 (each with 20 isolates). Eight pathotypes were identified from Lr9 and only two pathotypes were identified from Lr19. The most frequent pathotypes virulent to Lr9 were KTSPT (30%) followed by TTTMS (25%). Moreover, the other pathotypes ranged from 5 to 10%. Whereas, the most frequent pathotype virulent to Lr19 was CTTTT (85%) and the lowest PKTST was 15%. Pathotypes i.e. PRSTT, NTKTS and TTTMS identified from Lr9 were more aggressive on most of the tested leaf rust monogenic lines, as they were virulent to 36, 35 and 35 lines, respectively from a total of 39 lines. The two pathotypes; PKTST and CTTTT identified from Lr19 were virulent to 36 and 35 lines, respectively. Moreover, leaf rust pathotypes i.e. NPTNK and PRSTT from Lr9 and PKTST from Lr19 were the most aggressive on the tested wheat cultivars at seedling stage. The Lr2a was the most effective leaf rust resistance genes against the tested pathotypes at adult plant stage. Wheat cultivars Misr 1, Misr 2 and Nubariya 1 were the most resistant cultivars against the tested pathotypes at adult plant stage.
University of Mohammed V/ICARDA
HAFSSA,KABBAJ, AYED, AL ABDALLAT, GREGOR, GORJANC, JESSE, POLAND, MIKAEL, MILOUDI NACHIT, AHMED, AMRI, BOUCHRA, BELKADI, KARIM, FILALI MALTOUF, FILIPPO, BASSI MARIA, , , , , , , , , , , ,
Durum wheat (Triticum durum Desf.) is a major stable crop and it represents a base of the Mediterranean diet. This region is subject to a Mediterranean climate, which is extremely unpredictable with severe changes in moisture and temperature occurring each crop season. This unpredictability is summarized by breeders as GxE and the identification of traits controlling this interaction is quintessential to ensure stability in production season after season. To study the genetics of yield stability, four RILs populations derived from elite x elite crosses were assessed for yield and 1,000-kernel weights across five diverging environments in Morocco and Lebanon. These 550 RILs were characterized with 4,909 polymorphic SNPs via genotyping by sequencing. A consensus map was derived by merging the individual genetic maps of each population. Finally, imputation was used to fill all the missing haplotypes and reach a reduction of missing data to below 8%. Several significant QTLs were identified to be linked to TKW, grain yield and a stability index, namely AMMI wide adaptation index (AWAI). A second approach to identify loci controlling stability was the use of a global panel of 288 elites, accessions and landraces tested in 15 diverging environment. Multi-locations data were compiled via GxE models to derive the AWAI stability index. In addition, this panel was characterized with 8,173 polymorphic SNPs via Axiom 35K array. Significant associations were identified for all traits, including QTLs unique to AWAI. The sum of the identified QTLs can now be pyramid via marker assisted selection and molecular designed crosses in order to obtain very stable cultivars.
National Agronomic Institute of Tunisia
FATMA,BEN JEMAA, HAJER, SLIM-AMARA, , , , , , , , , , , , , , , , , , , , , , , , , ,
Wild species with valuable genetic heritage was used long time ago in interspecific crosses to improve cultivated plants adaptation to environmental constraints. The objective of this study is to transfer the salinity tolerance of Hordeum marinum, a wild barley species, to three durum wheat varieties (Karim, Razzek and Nasr) by intergeneric crosses. In order to skip the incompatibility between these species, in vitro immature embryo rescue was performed using B5 medium (Gamborg et al., 1968). The results showed that the genotype has an important effect on the success of the crosses and the rate of regenerated plants. We have found that 34.21% of the embryos derived from hybridization Razzek x Hordeum marinum has regenerated haploid plantlets, 5.88% for Karim x Hordeum marinum cross, and 2.78% for Nasr x Hordeum marinum.
The obtained chromosomal stock of the hybrid haploid plants was doubled by colchicine treatment concentrated at 0.05%. The rate of doubled haploid plants were reduced after colchicine treatment to 26.32% for Razzek x Hordeum marinum cross, 0% for Karim crossed with Hordeum marinum and remained unchanged for Nasr x Hordeum marinum.
The doubled haploids obtained are subjected to salt stress (6-12 g/l) in order to evaluate their tolerance to salinity.
University of Georgia
Mohamed,Mergoum, Yuanfeng, Hao, Jerry, Johnson, Dan, Bland, James, Buck, John, Youmans, Benzamin, Lopez, Steve, Sutton, Zhenbang, Chen, , , , , , , , , , , ,
Leaf rust disease, caused by the fungal pathogen Puccinia tritcina, is the most destructive foliar disease of wheat worldwide. Gene combination of Lr37/Yr17/Sr38 has been used in Georgia (GA) to prevent the loss from leaf rust; however, with the emergence of new virulent races, these genes have lost their effectiveness. 'AGS 2000' and 'Pioneer 26R61' are the most common soft red winter wheat (SRWW) cultivars in Southeastern US, and have been used as good sources of resistance to leaf and stripe rusts, and powdery mildew. To characterize the genetic basic of resistance of AGS 2000, a mapping population of 178 recombinant inbred lines (RIL) has been developed from a cross with Pioneer 26R61. This population was genotyped using a combination of SSR, DArT, and SNP markers, and a total of 2734 markers covering the entire genome were used for the construction of genetic map. Phenotypic evaluation of parents and RIL population was conducted at the seedling stage using a virulent GA leaf rust race. QTL mapping revealed a major QTL on chromosome 2BL, explaining about 20% of total phenotypic variation in AGS 2000. Additionally, a minor QTL was also detected on chromosome 5B. QTL on 2BL was identified as a novel gene, and can be used in marker-assisted selection for leaf rust resistance.