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[AgriLife Today] Genetic discovery another tool in battle against wheat pests

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By: Kay Ledbetter

Writer: Kay Ledbetter, 806-677-5608, [email protected]
Contact: Dr. Shuyu Liu, 806-677-5600, [email protected]

AMARILLO – Greenbug and Hessian fly infestations can significantly reduce wheat yield and quality in Texas and worldwide. Breeding for resistance to these two pests using marker-assisted selection just got a new tool from a Texas A&M AgriLife Research study.

Because genetics is the most economical strategy to minimize losses, AgriLife Research wheat geneticist Dr. Shuyu Liu began two years ago searching for breeder-friendly markers for those two insects. This step is a continuation of ongoing genetic work on insect resistance.

Through the years, a number of greenbug resistance genes have been identified in wheat and its relatives based on their differential reactions to different biotypes, which range from A through K. There are also 18 Hessian fly biotypes, and because it has the ability to overcome resistance genes deployed in wheat cultivars through mutations, it is necessary to identify and utilize resistance genes from diverse sources for wheat breeding.

Hessian fly adult. (Texas A&M AgriLife photo)

Scientists use genetic markers to identify regions where specific genes can be found on a particular plant. Liu has identified the neighborhoods or markers for a gene offering greenbug resistance, Gb7, and a gene that provides Hessian fly resistance, H32, in wheat.

Liu’s work was recently published in the Theoretical and Applied Genetics Journal of Plant Breeding Research, detailing the development of the Kompetitive Allele Specific Polymerase Chain Reaction or KASP assays for both genes.

 

Joining Liu on the publication were AgriLife Research wheat team members Drs. Jackie Rudd, Amarillo, and Amir Ibrahim, College Station, both wheat breeders; Dr. Qingwu Xue, crop stress physiologist; Dr. Chor Tee Tan, an associate research scientist; as well as other students and staff in Amarillo.

Dr. Shuyu Liu, a Texas A&M AgriLife Research geneticist in Amarillo, looks at the results from a KASP assay for insect resistant wheat lines. Clustered in blue are the resistant lines, the susceptible lines are clustered in red, and green indicates lines not pure resistant or susceptible. (Texas A&M AgriLife photo by Kay Ledbetter)

Both genes were identified through previous research, and linked markers for them were mapped, but the detection methods were not well suited for marker-assisted selection for evaluating thousands of plants, Liu said.

He said knowing an address doesn’t mean someone knows where in the city to start looking for it. But by developing single nucleotide polymorphism, or SNPs, which include flanking markers closely linked and located on chromosomes, geneticists are able to give breeders the neighborhood to search.

SNPs are then converted into KASP assays, which are considered breeder-friendly because they are easier to use, faster and more accurate, he said.

Effective molecular markers closely linked to the target genes are the key for the success of marker-assisted selection on traits such as greenbug and Hessian fly resistance, Liu said. For instance, a breeder will typically screen 1,000s of breeding lines, and the KASP acts as a flag to say the necessary genes for a particular trait exists in a particular line.

Through Liu’s work, both genes can now be easily transferred into a new wheat line through marker-assisted selection.

Liu said the Gb7 and H32 are both found in a synthetic wheat, W7984, which is a parental line for a mapping population that wheat researchers are using worldwide. Synthetic wheats are man-made crosses between Durum or pasta-type wheats and Aegilops tauschii. These initial crosses provide access to genes of the wild relatives of wheat, thus increasing usable genetic diversity for breeders to improve winter wheat varieties.

The mapping population was developed more than 10 years ago by the International Triticum Mapping Initiative, but neither of these genes has been used for resistance in breeding programs to this point, he said.

“The reason I think they were not being used is they were in a synthetic line and it required more effort to transfer them into adaptive wheat lines,” he said. “What we have done with the KASP marker is make them easier to find and utilize.”

For example, TAM 114, a newer, increasingly popular variety of Texas A&M wheat, does not have greenbug resistance and only has limited Hessian fly resistance, Liu said.

“But with this new knowledge, breeders can cross with TAM 114 and keep its superior end-use quality and improve it with the Gb7 and H32 genes,” he said. “This will make the new line more adaptable to the regions where Hessian fly is a problem.”

By crossing wheat lines with the identified KASP markers, the process to develop the pure line with selected properties can be much more accurate, Liu said.

Liu said he began searching for these markers because the TAM breeding program has made heavy use of synthetic germplasm so the markers will quickly be implemented.

To get to this point, Liu utilized genotype-by-sequencing markers developed by other research groups, and ultimately the KASP markers were validated using the set of synthetic wheat lines. Each line of that mapping population was screened for reactions by greenbug and Hessian fly by two U.S. Department of Agriculture Agricultural Research Service centers.

“We’ve determined they are very effective under many genetic backgrounds,” he said. “Genetic diversity and genetic gains are always important to wheat breeders.”

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Farm & Ranch

Meanwhile, Back at the Ranch…

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By Rayford Pullen | [email protected]

When May arrives, we start thinking about weed control. With two years of drought under our belts, grass grazed short and hay stocks depleted, what we do now will influence our forage conditions for the entire year. With 75 percent of our annual warm season forages made by July 15 in North Texas, we need to get the grass growing while the sun shines.

Speaking of the sun shining, the biggest deterrent to growing lots of grass is restricted sunlight, and the biggest sun blockers we have are weeds.

Have you noticed weeds are normally just slightly taller than your grass and are probably blocking 90 percent of the sunlight from reaching the grass itself? So obviously, we need to improve conditions, so sunlight reaches the plants we want to grow.

With grass extremely short, more sunlight is hitting the soil surface now, which in turn results in more weed seed germinating. With the moisture we have received, we expect an abundance of weeds this year.

To read more, pick up a copy of the May issue of NTFR magazine. To subscribe by mail, call 940-872-5922.

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Farm & Ranch

Land Market Report: March Land Sales

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By Jared Groce

Rural land sales are continuing on a steady pace for early spring, with prices holding very strong with the sell-to-list price ratios remaining very high, even on properties that have been on the market for a longer than usual time period. The total number of transactions are picking up once again as the spring selling season kicks off, and the average acreage continues to decrease.

Larger acreage properties seem to be in higher demand than smaller properties currently, with many buyers simply parking cash in real estate to hedge against inflation. Interest rates seem to have settled down and most experts agree that rates will be reduced by the fed this year. Some lenders have programs in place that allow the buyer to reduce their rates without having to go through a full refinance ordeal.

To read more, pick up a copy of the May issue of NTFR magazine. To subscribe by mail, call 940-872-5922.

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Farm & Ranch

Texas FFA State Vice President Weston Parr

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Future Farmers of America was founded by a group of farmers in 1928 with the mission of preparing the next generation of agriculture. It has done just that during its 95-year history, as the organization works to give back to others by following its motto, “learning to do, doing to learn, earning to live, living to serve.”

FFA is an organization made up of state associations, and at the helm of the Texas FFA is a team of 12 officers representing their respective areas within the Lone Star State. These individuals dedicate a year of their lives as they serve members, provide leadership, and work together with the state staff and board of directors to develop policy and lead the organization of over 177,000 members.

North Texas is represented by Area IV and Area IV, stretching from Wilbarger County to Bell County and from Runnels County to Grayson County. This year, those chosen to lead this great area are State President Isaac Hawkins Jr., Area IV, and State Vice President Weston Parr, Area V.

Parr is from the Sam Rayburn FFA chapter and the Area V Association, but the leader who now serves more than 19,100 members of Area V entered the FFA organization as a shy teenager who sat in the back of the room.

“I didn’t talk to a whole lot of people. I didn’t know what I wanted to do with my life or where I could see myself, so I wasn’t involved on my high school campus,” Parr recalled.

“Then I started FFA and slowly but surely, my ag teachers worked me into attending more contests, meeting new people, and speaking. I remember the first time I gave an officer speech to my chapter. I can still remember how embarrassing it was. To see the progression from that moment to speaking on stage at the state convention in front of thousands of people. Now I feel like I can enter the industry I want and be successful all because of what FFA afforded me for five years.”

There is not much Parr did not do during his time in high school. His contest participation included chapter conducting, wool judging, cotton judging, wildlife, and job interview, but his favorite was extemporaneous speaking, which he did not start until his senior year of high school.

“I wish I could go back to my freshman, sophomore, and junior years and start that sooner. I think if I had more time, I would have been more successful than I already was, but that was something I didn’t realize I liked at the time. I’m not naturally somebody who likes to speak in public, but it was actually my favorite,” Parr said.

Parr won several awards during his time competing. In 2023 alone, Parr earned the Texas FFA Service-Learning Proficiency title, was a National FFA Service-Learning Proficiency finalist, and a Texas FFA Extemporaneous Speaking finalist. In addition to his CDE and LDE events during high school, he showed commercial steers at Houston, and boilers at most major shows, participated in the county show with projects in ag mechanics, showed goats from time to time, and showed heifers until graduation.

“FFA provides invaluable resources and knowledge to be successful once you leave high school and you are out of the blue jacket for the first time. I have been a part of a lot of great organizations over the years, and they are all great in their own way, but in my opinion, FFA is the most successful at producing members of society who want to go and do something with themselves,” Parr said.

He was halfway through his time as Area V Association President and attending the national convention when he began to ponder the idea of running for state office.

“This is around the time when you usually figure out if you want to go through and be a state officer or you decide that area officer is your last run. I was unsure of where I wanted to go, but I knew I didn’t want to be done with FFA. I decided maybe it would be a good opportunity not only for me to make more friendships and connections, but also to give back to the program that allowed me to be able to do what I can do today,” Parr explained.

To read more, pick up a copy of the May issue of NTFR magazine. To subscribe by mail, call 940-872-5922.

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