A new hybrid plant has emerged in Kansas wheat fields. Through genetic and cytogenetic testing, it was determined to be a hybrid derived from wheat and triticale. This hybrid was confirmed in three locations in Kansas this year.
The mysterious hybrid was observed by Kansas Crop Improvement Association (KCIA) inspectors in Dickinson County (Fig. 1A) and Marion County (Fig. 1B). In addition, a producer from south-central Kansas also found the same hybrid (Fig. 1C).
Figure 1. A) Dried spike samples from Dickinson County; B) Dried spike samples from Marion County; C) Green spike samples from a producer in south central Kansas.
Samples from all three locations were sent to the National Agricultural Genotyping Center (NAGC) in North Dakota. The NAGC targeted both the rbcL gene and the ITS2 region in their DNA tests of the stem material. They confirmed all three samples were identical. The NAGC used the NCBI public database and searched for a match using the BLAST algorithm. Based on the database results, they reported that the ITS2 region suggested the samples contained nuclear genomes of Secale and a Triticum species.
The Wheat Genetic Resource Center (WGRC) at Kansas State University provided further testing through a cytogenetic analysis of the seeds produced by the hybrid. Cytogenetics is a branch of genetics that involves the study of chromosomes. The cytogenetic analysis determined that the hybrid plant had 48 chromosomes: 41 wheat and 7 rye (Figure 2). The rye chromosomes were labeled with red color and wheat chromosomes were stained with blue color. The result indicated that the hybrid plant is likely derived from natural hybridization between hexaploid wheat (AABBDD) and octoploid triticale (AABBDDRR).
Figure 2. Cytogenetic characterization of wheat-triticale hybrid. Rye chromosomes were painted in red and wheat chromosomes were stained with blue. GAA-FISH revealed the presence of only one 5B chromosome (arrow).
The samples KCIA gathered were collected while the spikes were still green and immature. An average of twenty sample spikes shows that each spike has approximately sixteen spikelets. However, most spikes have no seed fill. The samples tested by KCIA had between 0-3 seeds per spike. The KCIA seed lab performed a germination test with ten seeds. Six of the ten planted seeds produced healthy seedlings under normal wheat germination conditions (Figure 3).
Figure 3. KCIA germination test showing 60% viable hybrid.
In summary, the mystery plant found in Kansas wheat fields has been identified as a wheat x triticale hybrid. To my knowledge, this is the first time this specific hybrid has been found and identified. Over the course of my investigations, I grew tired of referring to it as “the wheat x triticale hybrid,” so I’ve informally started calling it “quadrotriticale” because it has both the Secale and Triticum species and to distinguish it from commercial triticale.
While the “quadrotriticale” has an overall low fertility, it may show up more in areas where a lot of triticale cover crops are being used. In addition, it may also appear if a farmer saves seed from a wheat field that was grown next to a triticale field. The “quadrotriticale” plants were discovered due to the careful field inspection procedures required for Certified seed production. The “quadrotiticale” plants found by KCIA inspectors grew a little taller than the wheat, making them easy to spot. Like its parents, the hybrid is a bunch-type plant that can be pulled easily if it is found in any production field. Now that this hybrid has been identified, KCIA growers can easily locate it and rogue it out of their Certified seed fields. KCIA’s excellent seed growers and our superior Certified seed standards are more than up to the task of dealing with this new hybrid and continuing to produce high-quality wheat seed.
Acknowledgments
- The cytogenetic analysis was done by WGRC at KSU. Thank you to Dr. Dal-Hoe Koo.
- The DNA sequencing was done by NAGC, ND. Thank you to Megan O’Neil and Zack Bateson.
- The seed germination test was done by KCIA Seed Lab. Thank you to Rayshell Colson.
- Thanks to Dr. Allan Fritz for his overall assistance with this project and help networking.
Marion Spiering, Manager of Field Services and Seed Certification, Kansas Crop Improvement Association
mskcia@kansas.net