A new quantitative genetics study makes a strong case for the yield testing strategies the International Maize and Wheat Improvement Center (CIMMYT) uses in its wheat breeding program.

The process for breeding for grain yield in bread wheat at the International Maize and Wheat Improvement Center (CIMMYT) involves three-stage testing at an experimental station in the desert environment of Ciudad Obregón, in Mexico’s Yaqui Valley. Because the conditions in Obregón are extremely favorable, CIMMYT wheat breeders are able to replicate growing environments all over the world, and test the yield potential and climate-resilience of wheat varieties for every major global wheat growing area. These replicated test areas in Obregón are known as selection environments (SEs).

This process has its roots in the innovative work of wheat breeder and Nobel Prize winner Norman Borlaug, more than 50 years ago.  Wheat scientists at CIMMYT, led by wheat breeder Philomin Juliana, wanted to see if it remained effective.

The scientists conducted a large quantitative genetics study comparing the grain yield performance of lines in the Obregón SEs with that of lines in target growing sites throughout the world. They based their comparison on data from two major wheat trials: the South Asia Bread Wheat Genomic Prediction Yield Trials in India, Pakistan and Bangladesh initiated by the U.S. Agency for International Development Feed the Future initiative, and the global testing environments of the Elite Spring Wheat Yield Trials.

The findings, published in Retrospective Quantitative Genetic Analysis and Genomic Prediction of Global Wheat Yields, in Frontiers in Plant Science, found that the Obregón yield testing process in different SEs is very efficient in developing high-yielding and resilient wheat lines for target sites.

The authors found higher average heritabilities, or trait variations due to genetic differences, for grain yield in the Obregón SEs than in the target sites (44.2 and 92.3% higher for the South Asia and global trials, respectively), indicating greater precision in the SE trials than those in the target sites.   They also observed significant genetic correlations between one or more SEs in Obregón and all five South Asian sites, as well as with the majority (65.1%) of the Elite Spring Wheat Yield Trial sites. Lastly, they found a high ratio of selection response by selecting for grain yield in the SEs of Obregón than directly in the target sites.

“The results of this study make it evident that the rigorous multi-year yield testing in Obregón environments has helped to develop wheat lines that have wide-adaptability across diverse geographical locations and resilience to environmental variations,” said Philomin Juliana, CIMMYT associate scientist and lead author of the article.

“This is particularly important for smallholder farmers in developing countries growing wheat on less than 2 hectares who cannot afford crop losses due to year-to-year environmental changes.”

In addition to these comparisons, the scientists conducted genomic prediction for grain yield in the target sites, based on the performance of the same lines in the SEs of Obregón. They found high year-to-year variations in grain yield predictabilities, highlighting the importance of multi-environment testing across time and space to stave off the environment-induced uncertainties in wheat yields.

“While our results demonstrate the challenges involved in genomic prediction of grain yield in future unknown environments, it also opens up new horizons for further exciting research on designing genomic selection-driven breeding for wheat grain yield,” said Juliana. 

This type of quantitative genetics analysis using multi-year and multi-site grain yield data is one of the first steps to assessing the effectiveness of CIMMYT’s current grain yield testing and making recommendations for improvement—a key objective of the new Accelerating Genetic Gains in Maize and Wheat for Improved Livelihoods (AGG) project, which aims to accelerate the breeding progress by optimizing current breeding schemes.

This work was made possible by the generous support of the Delivering Genetic Gain in Wheat (DGGW) project funded by the Bill & Melinda Gates Foundation and the UK Foreign, Commonwealth & Development Office (FCDO) and managed by Cornell University; the U.S. Agency for International Development’s Feed the Future initiative; and several collaborating national partners who generated the grain yield data.

Read the full article here: https://doi.org/10.3389/fpls.2020.580136

This story by Janet Lewis was originally posted on the website of the Borlaug Training Foundation.

On February 3rd of 2020, the International Center for Maize and Wheat Improvement (CIMMYT) launched its annual Basic Wheat Improvement Course (BWIC).  The Borlaug Training Foundation’s Janet Lewis had a chat with Fatima Camarillo Castillo, CIMMYT’s Global Wheat Program Training Coordinator, to discuss the course and her role as coordinator.

Janet Lewis: “Can you give our audience a brief description of the Basic Wheat Improvement Course?”

Fatima Camarillo Castillo: “The wheat improvement courses at CIMMYT are short-term programs designed to train breeders working on national agricultural programs from countries where wheat is a major staple crop. During the basic training program, we provide participants an overview of the breeding pipeline and review breeding methodologies utilized in the Global Wheat Program for developing superior wheat germplasm. We also review core concepts on support disciplines for breeding such as genetics, statistics, plant pathology, and physiology. A set of practical and hands-on exercises follow where trainees collaborate directly with scientists and technicians on breeding activities of the program.”

JL: “What is your main role as the Training Coordinator?”

FCC: “I organize the content of the programs and communicate with the scientists to conduct the course. I also contribute to the training by lecturing on basic statistics, programming and genetics. During the training course, participants submit reports and prepare an oral and poster presentation. I support them by providing feedback on these activities. With the assistance of the training team, we also facilitate all the accommodations and arrangements for the participant’s trips and lodging in Mexico.”

JL: “What sparked your interest in being the training coordinator at CIMMYT?”

FCC: “As an alumnus, I personally understand the value of being part of this course. My goal as the current coordinator is to contribute to ensuring food security worldwide through training and capacity building on wheat research!”

JL: “2019 was your first year as the training coordinator. What experiences captivated you the most from 2019?”

FCC: “My greatest experience last year was that, as a coordinator, you do not expect to learn. The class of 2019 was a wonderful group of bright researchers that challenged me to keep working to become a better teacher and scientist. Some of them already excel in specific disciplines, so they provide me invaluable support to cover the academic content of the program.”

JL: “The 2020 class started on February 4th. Do you have any special expectations this year? The Women in Triticum group is participating this year, yes?”

FCC: “We will spend a couple of weeks at the CIMMYT research station at El Batan and move to Ciudad, Obregón to complete the training. We hope that trainees will interact with current scientists already established in Obregón. In the past, trainees were assigned to specific research groups in the middle of the course, but this year trainees will be integrated into the breeding activities starting the first day of their arrival in Obregon! We expect this will expose and familiarize the trainees with the breeding pipeline on a larger scale.

This year we will also have the recipients of the Women in Triticum Early Career Award. All our young scientists that have dedicated their scientific career to wheat research from Ethiopia, Uruguay, Germany, India, China, Mexico, and Pakistan.”

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If you’d like to learn more about the Basic Wheat Improvement Course or any programs offered at CIMMYT, you can find them at https://www.cimmyt.org/events/