Department of Agriculture, Sunsari, Nepal
Wheat (Triticum aestivum L.) is one of the major cereal crops vital for global food supply. Most of the wheat crop in developing world including that of Nepal is either grown with limited irrigation or under rainfed conditions and thus face moisture stress at one or more growth stages limiting grain yield. An experiment was carried out at the Institute of Agriculture and Animal Science, Rampur to evaluate the genetic variability of selected drought adaptive traits in Nepalese wheat germplasm. The wheat genotypes evaluated comprised of Nepalese landraces and commercial cultivars, CIMMYT (International Center for Maize and Wheat Improvement) derived advanced introduction lines and three checks with differential drought adaptability. The wheat genotypes were grown in pots (single plant) arranged in a replicated split plot design in greenhouse under two contrasting moisture regimes, optimum and moisture stressed. The genotypes were evaluated for water use, water use efficiency, relative leaf water content and biomass production. The ANOVA (Analysis of Variance) revealed significant variation between environments and among the wheat genotypes for most of the traits studied. A wide range of variability was observed for water use, water use efficiency, biomass yield and relative leaf water content in moisture stressed and non-stressed environments. Nepalese cultivar Gautam showed a number of favorable drought adaptive traits, whereas, Bhrikuti was average in this respect. Based on the scores of drought adaptive traits recently released Cultivar (cv). Vijay was characterized as drought sensitive. A number of landraces and advanced breeding lines showed high level of water use efficiency and other positive traits for drought adaptation.
Lake Chad Research Institute, Maiduguri, Borno State-Nigeria
Dattijo Aminu, Zakari Goji Silas Turaki, Fatima Henkrar, Udupa Sripada
The research was conducted at ICARDA, Rabat. Twenty-four accessions were obtained from LCRI for marker analysis. Wizard Genomic DNA Purification Kit was used for DNA extraction. DNA was extracted by CTAB method and quantified using 1.0 % (w/v) agarose gels. Total of 12 loci, 5 functional and 7 linked random DNA markers to the traits of interest were used. PowerMarker and DARwin software were used to calculate the No. of alleles and values of genetic diversity, PIC, genetic distance, and NJ dendrogram. The total No. of detected alleles was 39; and mean No. of alleles was 3.25. No. of alleles range from 1 (Dreb-B1) to 9 (Xgwm577). Genetic diversity index ranged from 0.0000 in Dreb-B1 to 0.8471 in Xgwm577. The PIC value was also varied from 0.0000 (Dreb-B1) to 0.8296 (Xgwm577). The frequency of biotic resistance linked random DNA marker allele at Xgwm144 and Xwmc44, associated with yellow and leaf rust gene was 25% each. Marker alleles Xgwm577 and Xgwm533 linked to Stb2 and Stb8 at 150 and 120bp have frequencies of 21 and 4%. The frequency of abiotic resistance showed 50% of accessions had 1R segment (1BL.1RS translocation) and 58% of accessions showed presence of 120bp allele of Xwmc89, associated with QTL for drought tolerant. Functional marker alleles of Dreb-B1 associated with drought tolerant genes showed alleles frequency in all accessions. Linked marker allele Xgwm111 linked to heat tolerant gene showed 17% allele frequency at 220bp. Rht1 and Rht2, the allele frequencies were 92 and 4%. 92% of the cultivars had photoperiod insensitive allele at Ppd-D1 locus. VrnA1a and VrnA1c primer pair amplified at 965, 876, and 484bp, allele frequency of 13 and 87%. Cluster analysis had grouped the accessions into 5 at a genetic distance level 0.15.
KENYA AGRICULTURAL AND LIVESTOCK RESEARCH ORGANIZATION (KALRO)
Godwin Macharia, Bernice Ngina
Studies have shown that women farmers are worse off than the male counterparts in terms of adoption of improved varietal technology and hence they experience low productivity. This technology adoption gender gap affects agricultural development considering that women in Kenya play a significant role in agriculture and food production. The link between gender and adoption is likely to vary across cultures and over time. The hypothesis of significant gender differences in access to and use of productive resources and adoption of improved wheat varieties was tested. Based on bivariate analysis, significant differences in access and use of productive resources between men and women farmers were observed. Men were more likely to access credit, extension services, own and cultivate more lands compared to women. Similarly, women in female-headed households were less likely to access the productive resources compared to women in male-headed households. The factors that affect adoption of improved wheat varieties among smallholder farmers were analysed with a specific focus on women. In contrast to the conventional model of using gender of the household head, gender and plot levels analyses were conducted. The results show that the gender of the field owner had a negative effect on adoption of improved wheat varieties. This indicates that, men were more likely to adopt improved wheat varieties, compared to women farmers. Moreover, the level of education of the household head, household size, and access to credit and extension services were observed to significantly increase the likelihood of farmers adopting improved wheat varieties. In the same framework, female farmers in male-headed households who had access to credit were more likely to adopt improved wheat varieties while there was greater probability of adoption of improved wheat varieties among female farmers in female-headed households who had access to agriculture extension and belonged to a farmer organization
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.
Ethiopian Institute of Agricultural Research
Ashenafi Gemechu, Habtamu Tesfaye, Zerihun Tadesse, Habtemariam Zegeye, Netsanet Bacha, Ayele Badebo, Bekele Abeyo, Pablo Olivera, Matthew, Rouse
Puccinia graminis f. sp. tritici (Pgt) is the major wheat production constraint in Ethiopia causing recurrent epidemics that resulted in the withdrawal of widely grown wheat cultivars from production. Among the current Pgt races detected in Ethiopia, TKTTF is the most frequent and has caused a severe epidemic in the south wheat growing regions (Bale and Arsi) after its first detection in 2012. Therefore, to avert the current situation, identifying sources of resistance to race TKTTF in breeding germplasm is a top priority to the National Wheat Breeding Program. Hence, 82 promising bread wheat lines including five check cultivars were evaluated in Debre Zeit in a TKTTF single race nursery for three consecutive seasons, 2014-2016. Ethiopian bread wheat cultivar Digalu was used as a spreader row and was inoculated using a single isolate of race TKTTF at different growth stages. The nursery was bounded by oat to reduce interference with any other stem rust race. The 82 lines were tested in the greenhouse at Cereal Disease Laboratory and were also tested with known diagnostic molecular markers. Twenty-nine lines displayed low levels of terminal stem rust severity in the field and low coefficient of infections. Fourty-one lines were resistant to race TKTTF at the seedling stage. Bread wheat lines resistant to TKTTF are valuable sources of resistance that can be deployed in wheat growing regions of Ethiopia prone to stem rust.
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.
Wheat Program, National Agricultural Research Center (NARC) Islamabad
Sikander Khan Tanveer, Muhammad Sohail, Muhammad Shahzad Ahmed, Sayed H. Abbass, Sundas Wagar, Atiq Rattu, Muhammad Imtiaz
Wheat plays a vital role in multifaceted farming system of Pakistan. Like other many other countries, Pakistan's sustainable wheat production is also continuously threatened by a number of biotic and abiotic stresses. Among the biotic stresses, three rust diseases of wheat have been the most devastating. Stem rust was effectively controlled with adoption of the semi-dwarf spring wheats of the Green Revolution. However, the threat of the evolution of Ug99 race of stem rust in East Africa and its migration to Iran cannot be neglected. The Chance of of Ug99 migrating from Iran into Pakistan, coupled with the presence of dangerous new races of stripe and leaf rusts invites enormous efforts for development of rust resistant varieties for sustainable production of the wheat in the country. In this regard the Wheat Program, NARC, Pakistan initiated an intensive breeding program with financial and technical support of USDA and CIMMYT. Diverse sources of resistance to the three rusts particularly to the stem rust race Ug99 were introduced from CIMMYT. Through the rigorous selection procedure, four rusts resistant wheat varieties (NARC 2011, Pakistan 2013, Zincol 2016 and Borlaug 2016) have been released. These varieties are also resistant to Ug99. The varieties i.e. NARC 2011, Borlaug 2016 and Zincol 2016 are performing well in irrigated areas whereas Pakistan 2013 is suitable for rainfed conditions. The variety Zincol 2016 has high Zn content (35 ppm) in grain as compared to national standard check variety (25 ppm). These varieties are not only higher yielding but also possess good grain quality and other desirable traits. A considerable quantity of seed of the varieties is already present in the national seed system and will reduce the risk of Ug99 threat.
Ravi,Singh, Julio, Huerta-Espino, Mandeep, Randhawa, , , , , , , , , , , , , , , , , , , , , , , ,
Wheat leaf rust (LR) and stripe rust (YR), caused by the air-borne fungi Puccinia triticina (Pt) and Puccinia striiformis f. sp. tritici (Pst), respectively, are considered the primary biotic threats to bread wheat and durum wheat production globally. Growing resistant wheat varieties is a key method of minimizing the extent of yield losses caused by these diseases. Bread wheat lines Francolin #1, Kenya Kongoni, Kundan and Sujata, and CIMMYT-derived durum wheat lines Bairds and Dunkler display an adequate level of adult plant resistance (APR) to both leaf rust and stripe rust in Mexican field environments. Six recombinant inbred line (RIL) populations developed from crosses Avocet/Francolin #1, Avocet/Kenya Kongoni, Avocet/Kundan, Avocet/Sujata, Atred#1/Bairds and Atred#1/Dunkler were phenotyped for leaf rust response at Ciudad Obregon, Mexico, and the bread wheat populations for stripe rust response at Toluca for under artificial inoculations for multiple seasons. The RIL populations and their parents were genotyped with the 50 K diversity arrays technology (DArT) sequence system and simple sequence repeat (SSR) markers. Known pleotropic APR genes Lr46/Yr29 mapped in all of six populations, and explained 7.4-65.1% and 7.7-66.1% severity variations for LR and YR across different bread wheat populations and accounted for 12.4-60.8% of LR severity variations over two durum wheat populations. In addition, several new APR loci identified on chromosomes 1AS, 1DS, 2BS, 2BL, 3D and 7BL in bread wheat and QTL on chromosome 6BL in durum wheat. Among these loci, QTL on chromosomes 1AS, 3D and 7BL might be represent new co-located/pleotropic loci conferring APR to LR and YR. RILs combining these APR loci can be used as sources of complex APR in both bread wheat and durum wheat breeding. In addition, the closely linked single nucleotide polymorphism (SNP) markers have been converted into breeder-friendly kompetitive allele specific PCR (KASP) markers and their diagnostic verified.
Leonardo,Crespo-Hererra, Julio, Huerta, Ravi, Singh, , , , , , , , , , , , , , , , , , , , , , , ,
Malnutrition affects more than 2 billion people across the globe, particularly zinc and iron deficiency causes major health problem in developing world. The biofortified staple food crops such as wheat, is an important channel to contribute to the hidden hunger problem in low income countries. Breeding for enhanced zinc concentration in wheat was initiated by crossing high zinc sources identified among synthetic wheats, T. dicoccum, T. spelta and landraces. These crosses have resulted in wheat varieties with competitive yields and enhanced grain zinc were adapted by farmers in South Asia. CIMMYT-derived early-maturity wheat cultivar 'Zinc-Shakti' with about 40% increased zinc (+14 ppm), is now grown in eastern India through public-private partners. The two CIMMYT-derived biofortified varieties: 'WB2' and 'HPBW01' released in 2016 for northwestern plains zone of India. In Pakistan, 'Zincol' was released in 2016. The first high zinc wheat variety (Bari-Gom 33) with better resistance to wheat blast have been released in Bangladesh for commercial cultivation in 2017. Targeted crosses with increased population sizes were used to obtain superior progeny lines that have high zinc levels in combination with other essential traits. This has resulted in the incorporation of several novel alleles for grain zinc and iron in elite, high-yielding germplasm. High zinc and iron are under quantitative genetic control and further progress is possible as multiple QTL are pyramided in high yielding wheats. High-throughput, non-destructive phenotyping for grain zinc and iron using the X-ray fluorescence (XRF) analysis has facilitated the selection dramatically. Gene discovery and mapping studies leading to the utilization of markers to further improve the breeding efficiency. Rapid adoption of high zinc wheat varieties in South Asia and beyond is expected with the second wave of high zinc wheat lines with superior yield, heat and drought tolerance and resistance to rusts and other foliar diseases.
University Mentouri of Constantine, Algeria
Wheat is the world's most widely grown food crop. New races of pathogens frequently overcome current resistant varieties. To address this issue Algeria has strategies for immediate action, medium term protection and long-term research efforts to develop new resistant wheat varieties. Yellow rust is a very important disease of wheat in Algeria where 60% of the wheat crop is grown under cooler high elevation climate conditions (2?C ? 15?C). Crop losses reached 80% during the 2004/2005 epidemics. Strategies adopted to reduce the risk of wheat rust are ongoing yearly surveillance, awareness, and early warning systems to farmers; and breeding and developing new varieties with high yield potential and durable resistance. Several highly resistant varieties (Tiddis, Boumerzoug, Massine, Akhamokh and Yacine) were selected and promoted following seed multiplication and commercial release. They are also widely used in crosses to improve local varieties. The newly released varieties are being distributed to farmers that grow susceptible varieties. This gene deployment will provide a natural barrier between eastern to western Algeria to intercept the major direction of air flow. Fungicide control is now routinely applied soon after rust detection or even preemptively. The level of awareness for wheat rusts across Algeria is now very high. Training among farmers for visual detection is widely promoted by plant protection and extension services. These strategies have been very effective in mitigating the threat of wheat stripe rust such that losses have not exceeded 10% over the last five years.