Breeding Improved SRW Wheat Varieties for Kentucky

Breeding Improved SRW Wheat Varieties for Kentucky June 10, 2021 Dave Van Sanford Executive Summary Sustainability: Our research is designed to breed and release superior SRW wheat varieties for Kentucky growers. We incorporate sustainability into the breeding program by focusing on disease resistance in order to reduce fungicide use, for example. We search for those breeding lines that show greater nitrogen use efficiency and thus require less N fertilizer, increasing the economic and environmental sustainability of the grower’s wheat enterprise. We endeavor to breed high- yielding, early maturing varieties with excellent test weight and straw strength that will meet the social goal of sustainability by filling food needs and enhancing environmental and economic sustainability by reducing soil erosion and increasing economic sustainability through improved profitability of the 3-crops-in-2-years rotation. Plan of Work: Crossing: To begin our research cycle, in mid - August we must first vernalize our winter wheat parental lines in a cold- room at 39° F for 9 weeks so that they will flower. Vernalized seedlings are transplanted in October and then every 3 weeks until early December. Continuous plantings of parental lines insures that we will have flowering plants to work with from late November through early spring. Crossing is completed in early April as we get busy with fertilizer and herbicide applications and other field-work. We choose parents to cross based on several factors: testing performance in replicated yield trials (yield, test weight, height, lodging, earliness), scab resistance measured in our scab nursery, and genomic predictions of high yields and test weights, early maturity, lodging resistance, good milling quality and scab resistance. The purpose of making these crosses is to create new genetic variation so we can reach higher agronomic, disease resistance and quality levels. We spend a great deal of time after harvest analyzing data and selecting lines to be used as parents with a special focus on superior performance in multi-year, multi-location trials including scab nurseries in other states throughout our region. Population and Line Development and Genomic Selection: We begin planting field plots and headrows by October 10 and aim to finish by mid - November. The F1 hybrids from the greenhouse are planted in individual rows in the field to produce enough F2 seed that we can begin screening for important visual traits. From F2-F4, we select well-filled, disease- free heads in the most vigorous plots and rows. In the F5 generation, we plant seed from individual heads in headrows, and select 15 heads from the most vigorous, disease-free rows. These heads are planted in headrows and we send tissue of these lines to a lab for DNA sequencing and genomic predictions. Based on genomic predicted values of yield, heading date, height and scab resistance, and the observed vigor, straw strength, height, heading date and disease resistance of rows, we select lines for yield testing. We conduct whole grain quality analysis of the selected rows to get an early read on milling and baking quality. Lines with poor performance potential based on genomic predictions can be eliminated and we save the time and money we would have spent on field testing them. Yield Testing: Our 2021-22 yield trial locations are: Lexington, Woodford Co., Princeton, and Schochoh. We will also test 25-30 lines in multi-state cooperative tests – Mason Dixon, 5 state and Uniform Eastern Nurseries. These replicated tests let us measure agronomic performance and disease resistance along with milling/baking quality in KY and surrounding states. Purification and Increase: We send approximately 1000 advanced headrows to Yuma, AZ in September and then plant the 2-3 lb of genetically pure seed produced there in KY increase plots next year to produce breeder seed of potential variety releases. Head scab screening: Approximately 4000 rows of varieties, breeding lines, populations and cooperative nurseries are grown in our inoculated, irrigated scab nursery at Lexington where disease pressure is increased to epidemic levels. Scab infection severity, Fusarium damaged kernels and DON level are measured in each line; we eliminate susceptible lines from the breeding program. Speed Breeding: We are using LED lights and reduced vernalization time as an alternative to doubled haploids that will still accelerate our generation time: we can go from F1 to F4 - 3 generations in one year - and reduce line development by 4 years. We will purchase more LED lights to install in the greenhouse and expand this program.