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A total of 41 bread wheat (Triticum aestivum L.) varieties have been released so far in Nepal since 1960. Farmers have been gradually adopting newly released varieties due to disease and lodging resistance, better yield performance and good taste. In Nepal, wheat area coverage, production and productivity have been increased by almost seven, sixteen and two folds, respectively in the last 56 years. Performance of varieties varies from one region to another. Yellow rust is the major problems in hills while leaf rust is the primary issue on the plains. Stem rust is sporadic in localized areas of Nepal. Wheat research program in Nepal has released 9 wheat varieties resistant to Ug99 namely Vijaya, Tilottama, Banganga, Gaura, Dhaulagiri, Danphe, Sworgadwari, Munal and Chyakhura. Vijay, Tilottama and Banganga are also resistant to leaf rust while, Dhaulagiri, Danphe, Sworgadwari, Munal and Chyakhura are resistant to yellow rust. Since the release of Vijay, the first Ug99 resistant variety in Nepal during 2010, source seed production of rust resistant varieties has been increasing significantly each year with present coverage under these varieties being around 40%. WK 1204 has been occupied 35% area in hills of Nepal. Seed production and distribution of such high yielding disease resistant varieties through public-private partnership is leading to quality seed supply for varietal diversity and better food security in the country.
An effective partnership between CIMMYT, KALRO, EIAR and Delivering Genetic Gains in Wheat (DGGW) project on global stem rust phenotyping has made a significant progress and impact on the Global wheat community in addressing the threat of Ug99 race group and other important stem rust races in the region. International stem rust phenotyping networks play a key role in evaluating global wheat germplasm from many countries and institutions: identifying new sources of resistance, pre-breeding, CIMMYT-Kenya shuttle breeding, pathogen survey and surveillance, varietal release and genomic selection. About 600,000 lines have been screened against Pgt race Ug99 and derivatives since 2005, and the screening capacity at KALRO has increased to 50,000 lines each year from over 20-25 countries and research institutions each year. The results from international nurseries show a shift to higher frequencies of lines with resistance to race Ug99 since the screening activities were initiated in 2008.
KALRO and EIAR and several national programs have a dynamic and successful breeding programs that benefit from collaboration, testing, and release of materials coming out of the CIMMYT breeding program. The release of over 15 varieties in Kenya as well as in Ethiopia and more than 90 varieties released in several countries globally over the years is a testament to the success of the program. with spillover effects of varieties released in Burundi, Rwanda, and Uganda.
CIMMYT-Kenya shuttle breeding has resulted in rapid recycling of over 2000 breeding populations each year between Mexico and Kenya to evaluate and select lines in early generations against virulent stem rust races in Kenya to ensure lines have adequate levels of resistance are advanced not only in early generations of breeding cycle but also materials in the yield trails (10,000 annually) that are later constituted as international nurseries and distributed to National programs and partners.
To reduce losses caused by rusts, regular and timely replacement of susceptible varieties with new high yielding, rust resistant varieties must occur. Data from a farmer survey carried out across Pakistan (Punjab, Sindh, KPK and Baluchistan) in 2014 enabled an analysis of the uptake of rust resistant variety NARC 2011. The empirical results indicated that the major sources of information that farmers obtained about NARC 2011 were research stations (83%), seed companies (7%) and fellow farmers (5%). Although production inputs were applied equally to both rust resistant NARC 2011 and rust susceptible wheat varieties the average yield of NARC 2011 (5,063 kg/ha) was superior to high yielding but rust susceptible varieties (4,446 kg/ha). Quality attributes of NARC 2011, including taste, color, dough kneading and chapatti making properties, were preferred by >70% of farmers). Seed availability and accessibility of NARC 2011 were major issues. Farmer awareness of rusts, especially the threat of exotic Pgt race Ug99, needs to be improved.
The climatic conditions of Kazakhstan are suitable to grow the high-quality grain of spring wheat on an area of 12-14 mil.ha. The country’s sharply continental climate limits the wheat yield as well as biotic stresses. Among latter factors, diseases significantly reduce yield up to 25% and more during epyphytoties. In the Northern Kazakhstan the considerable threat for common wheat comes from leaf rust (Puccinia triticina), stem rust (Puccinia graminis), septoria (Stagonospora nodorum, Septoria tritici), and tan spot (Pyrenophora tritici-repentis); yellow rust (Puccinia striiformis) infects wheat plants in the South and South-east regions, where the winter wheat is more common. Epiphytoties of leaf rust were observed in 2000, 2002, 2005, and 2007. Many years research has led to conclusion that local wheat varieties do not possess resistance to mentioned diseases. Last year screening of 46 cultivars at Kostanay province designated virulence to local pathotypes, except of couple of them (Kazakhstanaskaya 19 and Karabalykskaya 20). Russian varieties (Omskaya 37, Omskaya 39, Omskaya 41, Uralo-sibirskaya, Pamyati Mayestrenka, Lyubava, and Altayskaya zhnitza) demonstrated “slow rusting”. In the period of 2001-2014 the effectiveness to leaf rust was identified using Thatcher isogenic lines under northern Kazakhstan conditions and showed avirulence to local Pt pathotypes in lines carrying Lr9, Lr24, Lr29, Lr35, and Lr37 as well as the pyramid of Lr genes and/or “slow rusting” genes. The essential spread of stem rust was recorded in 2007, 2008, 2013, and 2014. Taking into account the absence of local sources of infection. In addition, the monitoring of pathogen with use of a set of lines with Sr genes detected the absence of aggressive race within north of Kazakhstan. In order to create resistant cultivars the sources of resistance are recommended to apply from current study.
Wheat rust is a group of deadly, constantly changing fungal pathogens that pose a serious threat worldwide and also equally most important in Pakistan. Three participatory wheat seed value chain workshops conducted in Pakistan in 2014 indicated the predominance of informal seed systems in Khyber Pakhtunkhwa and Pothwar region of Punjab. A relatively old and rust susceptible variety Sahar06 was covering nearly 50% area of irrigated wheat in Punjab while the coverage of TD-1 was nearly 75 % of wheat area in Sindh. Predominance of mega susceptible varieties with informal seed systems can be an important recipe for the outbreak of rust diseases threatening the stability of wheat production systems in Pakistan. It is challenging to continue to improve and sustain wheat productivity by reducing vulnerability of wheat varieties to rust diseases, both in time and space when more than 70% of wheat seed used comes from farmers' own farm saved seeds mostly of old and obsolete varieties. To address this, 17 recently released rust resistant wheat varieties with diversity in genetic background, adaptation and good yield potential have been deployed through a network of partners to nearly 10,000 smallholder farmers in parts of 62 districts of Pakistan. Varietal deployment was done by coordinating on farm participatory varietal selection with agronomic interventions and village level seed multiplication and marketing. Though, rusts pathogens can evolve into new strains that are more virulent and damaging to wheat crops, nevertheless, some of these varieties do carry known genes conferring resistance to yellow, leaf or stem rusts thereby help avert any sudden rust epidemics. This effort will be instrumental in improving the access to new seed varieties in the grassroots level and widening the genetic bases of wheat that will help in buffering the rust incidence and contribute to household food security of smallholder farmers in Pakistan.
With ongoing threats of rust from both internal and international sources it has become a priority at CIMMYT and for Pakistan national programs to accelerate the rate of seed increase and to popularize new Pgt race Ug99 resistant varieties to avert future disasters. Seed of Ug99 resistant varieties NARC-11, Pak-2013, Dharabi-2011 and BARS-09 was produced under the Wheat Productivity Enhancement Program (WPEP). The country-wide participatory approach involves a partnership of farmers, seed companies and research institutes. In 2014 16,020 and 6,085 kg of seed of NARC-11 and Pak-13, respectively, were distributed all over the country, including Azad Jammu Kashmir and Gilgit-Baltistan. Comparative yields across Pakistan show that the rust resistant varieties are equal, or superior, to current stem rust susceptible varieties grown by farmers. Deployment and use of these varieties by farmers in Balochistan will have a significant impact not only on productivity, but may also avert the consequences of possible introduction of race Ug99.