Goat grass gives wheat breeders an edge

31 January 2018
by Laura Strugnell

A commentary published on 30 January in the leading science journal Nature Plants highlights the importance of an ancient grass species for wheat breeding. The commentary was sparked by the recent publication of a reference genome from Aegilops tauschii, also called goat grass.

Bread wheat was created some 10,000 years ago by a natural cross of more simple, primitive wheats with a sub-species of goat grass. As such, goat grass genes constitute a major component of the very large wheat genome. The sequencing of goat grass DNA opens the way for wheat breeders to apply a number of advanced approaches to improve the speed and precision of wheat breeding for important traits that may be found in the goat grass segment of the wheat genome.

The International Maize and Wheat Improvement Center (CIMMYT) and the International Centre for Agricultural Research in the Dry Areas (ICARDA) have produced many wheat x grass crosses, recreating the original, natural cross but using other goat grass species and thus greatly expanding wheat’s diversity. Wheat lines derived from those crosses have since been used in breeding programs worldwide and have helped farmers to boost yields by up to 20 percent. Goat grass is known for being highly adaptable and disease tolerant, so the crosses endow wheat with similar qualities. Varieties from these crosses make up over 30 percent of international seed stores.

Researchers expect that the sequencing of this grass species’ DNA will facilitate advanced approaches such as “speed breeding” – a technique that uses controlled variables to achieve up to seven rounds of wheat crops in one year. This will help allow wheat breeding to keep up with the rising global demand for the crop and to address the challenges of new, virulent diseases and more extreme weather.

Read the Nature Plants article: The goat grass genome’s role in wheat improvement. 2018. Rasheed, A., Ogbonnaya, F.C., Lagudah, E., Appels, R., He, Z. In: Nature Plants.

Now available: 2016-17 Annual Report of the International Wheat Yield Partnership

Wheat breeding lines from the IWYP Hub at CIMMYT are out-yielding local checks in tests, validating the strategy of combining high biomass individuals with those that feature better grain filling attributes. The lines are being sent to public and private breeding programs worldwide. Read more about this and other exciting IWYP activities and outputs:

Annual Report

Agricultural researchers forge new ties to develop nutritious crops and environmental farming

By Mike Listman/CIMMYT

EL BATAN, Mexico (January 25, 2017)—Scientists from two of the world’s leading agricultural research institutes will embark on joint research to boost global food security, mitigate environmental damage from farming, and help to reduce food grain imports by developing countries.

At a recent meeting, 30 scientists from the International Maize and Wheat Improvement Center (CIMMYT) and Rothamsted Research, a UK-based independent science institute, agreed to pool expertise in research to develop higher-yielding, more disease resistant and nutritious wheat varieties for use in more productive, climate-resilient farming systems.

Advances toward breaking the wheat yield barrier: IWYP 2015-16 annual report

 By Jeff Gwyn/IWYP

COLLEGE STATION, Texas (September 26,2016)- In addition to incisive background on IWYP, including its model, mission and goals, this report covers first-year activities and advances from thcover-iwyp-ar-2015-16e partnership’s Science Program and how research outputs are uses to generate added value.

Dr. Richard Flavell FRS, CBE, who chairs the Science Impact and Executive Board of IWYP, states: “Being a part of such a worthy endeavor as IWYP that seeks to impact global food and nutritional security by seeking solutions with cutting-edge science is exhilarating. This is a unique opportunity to employ and validate a new way of working together internationally to achieve common goals that address critical needs. We are confident that we have laid the necessary groundwork and will remain focused and committed to realize our collective success.”

To view or download a copy of the IWYP Annual Report follow the link: http://iwyp.org/annual-report/

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.