Posts Tagged ‘Genebank’

Wheat-rye crosses provide control for deadly sap-sucking aphid

Pictured are Martin Kropff, CIMMYT director general (left) and Mustapha El-Bouhssini, ICARDA entomologist, in that center’s lab at Rabat, Morocco.

In an excellent example of scientific collaboration spanning borders and generations, Mustapha El-Bouhssini, entomologist at the International Centre for Agricultural Research in the Dry Areas (ICARDA), screened wheat breeding lines from the International Maize and Wheat Improvement Center (CIMMYT) under glasshouse infestations of Russian wheat aphid (Diuraphis noxia), a major global pest of wheat. At least one of the lines, which were developed through crosses of wheat with related crop and grass species, showed high levels of resistance.

Scientists at CIMMYT began research on sources of RWA resistance for wheat in the early 1990s. Good sources of resistance from rye were accessed via wide crosses that combined major portions of both crop’s chromosomes, in collaborative work led by Adam J. Lukaszewski, University of California, Riverside.

“In our experiments, we did an initial screening with one replication and then a replicated test with a Pavon line and the check,” said El-Bouhssini.

Pavon is a semi-dwarf wheat variety developed by Sanjaya Rajaram, former CIMMYT wheat director and 2014 World Food Prize laureate. The version of Pavon referred to by El-Bouhssini had been crossed with rye by Lukaszewski and entered CIMMYT’s wheat genetic resource collections; the check was a popular high-yielding variety with no resistance to Russian wheat aphid.

Pavon had been used by Lukaszewski and colleagues as a model variety for wide crosses to transfer pest and disease resistance to wheat from its distant relatives. More recently Leonardo Crespo-Herrera, CIMMYT wheat breeder, pursued this research for his doctoral studies. It was he who provided a selection of wide-cross lines to El-Bouhssini.

“Resistance to pests in wheat is a valuable trait for farmers and the environment,” said Crespo-Herrera. “It can protect yield for farmers who lack access to other control methods. For those with access to insecticides, it can minimize their use and cost, as well as negative impacts on the environment and human health.”

 

The resistant wheat line (center) is green while all others have perished under heavy infestation of Russian wheat aphid, in the ICARDA entomology lab at Rabat, Morocco.

Mobilizing seed bank diversity for wheat improvement

During centrifugation, the emulsion for DNA extraction separates into two distinct phases. Chloroform:octanol is more dense than water solutions, so it forms the lower (green) layer. It is also more chemically attractive to molecules such as proteins and polysaccharides. These are thus separated out from the DNA, which is contained in the upper aqueous phase. This clear solution is carefully transferred to fresh centrifuge tubes using a pipette. Photo credit: CIMMYT. See the "DNA extraction" set that this photo is part of for more information and images.By Mike Listman/CIMMYT

EL BATAN, Mexico (January 12, 2016)-A recent study by a global team of researchers from CIMMYT, ICARDA, and the Global Crop Diversity Trust has uncovered a treasure trove of wheat genetic diversity to address drought and rising temperatures—constraints that cut harvests for millions of farmers worldwide and which are growing more severe with each passing year.

The team studied the molecular diversity of 1,423 spring bread wheat accessions that represent major global production environments, using high quality genotyping-by-sequencing (GBS) loci and gene-based markers for various adaptive and quality traits.

They discovered thousands of new DNA marker variations in landraces known to be adapted to drought (1,273 novel GBS SNPs) and heat (4,473 novel GBS SNPs), opening the potential to enrich elite breeding lines with novel alleles for drought and heat tolerance. New allelic variation for vernalization and glutenin genes was also identified in 47 landraces from Afghanistan, India, Iran, Iraq, Pakistan, Turkmenistan, and Uzbekistan.

Mean diversity index (DI) estimates revealed that synthetic hexaploids—created by crossing wheat’s wild grass ancestor Aegilops tauschii with durum wheat—are genetically more diverse than elite lines (DI = 0.267) or landraces (DI = 0.245). Lines derived from such crosses are already playing an increasingly important role in global and national breeding programs.

Identifying and mobilizing useful genetic variation from germplasm banks to breeding programs is key to sustaining crop genetic improvement.  The results have already been used to select 200 diverse germplasm bank accessions for pre-breeding and allele mining of candidate genes associated with drought and heat stress tolerance, thus channeling novel variation into breeding pipelines.

Published in the paper Exploring and Mobilizing the Gene Bank Biodiversity for Wheat Improvement, the research is part of CIMMYT’s ongoing Seeds of Discovery project visioning towards the development of high yielding wheat varieties that address future challenges from climate change.

ICARDA Awarded Gregor Mendel Innovation Prize

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Aleppo Genebank Team/ ICARDA

By Katie Lutz/CIMMYT

EL BATAN, Mexico (March 19,2015)- The Gregor Mendel Innovation Prize is awarded each year to an individual or an organization for outstanding contribution in plant breeding. Today, 19 March, The International Center for Agricultural Research in the Dry Areas (ICARDA) was presented this honor in Berlin. The award was presented to director general, Mahmoud Solh, and  ICARDA’s Genetic Resources Section (GRS) team.

Over the last three years, ICARDA has been faced with the looming situation in Syria. Last year, ICARDA’s headquarters in Aleppo was seized by Syrian rebel groups and ICARDA has had to disperse their staff and leave their headquarters in Syria. A group of researchers have put their own safety concerns aside, because leaving Aleppo would be a dramatic loss for ICARDA and international agricultural research. Among the researchers who stayed behind was ICARDA’s GRS team. The GRS team maintains the ICARDA genebank, which stores the world’s largest collection of barley, faba and lentil beans, along with ancient varieties of durum and bread wheat.