Targeted and efficient transfer of value-added genes into a wheat variety

With an objective to optimize an approach to transfer value-added genes to a wheat variety while maintaining and improving agronomic performance, two alleles (Als1 and Als2) with mutations in the acetolactate synthase (ALS) gene located on the long arm of wheat chromosomes 6B and 6D providing tolerance to imazamox herbicide were transferred to Eltan, a popular soft white common winter wheat cultivar in the Pacific Northwest (PNW), USA. Four-step marker-assisted background selection and marker assisted forward breeding approaches were used to develop a wheat variety carrying two genes (Als1 and Als2) for imazamox tolerance along with improvements in many other agronomic traits. Screening of 1600 BC₁ plants for imazamox tolerance identified 378 plants that were further screened with markers to identify seven plants that were used to make a population of 1400 BC₂ plants, and the selection cycle was repeated. Progeny of 17 selected BC₂F₁ plants was evaluated for various agronomic and quality parameters to select 12 plants that were increased for field testing. Field evaluation of these lines conducted over 58 location-years along with evaluation in the greenhouse/growth chamber led to the selection of a line “WA8143” carrying the two genes for imazamox tolerance that yielded >3% higher than Eltan did. With 96.8% similarity to the recurrent parent, WA8143 also showed a better disease resistance package and grain quality needed in a successful Pacific Northwest wheat variety and was subsequently released for cultivation under the name of “Curiosity CL+.”