Wheat Breeding and Genetics

Non-Technical Summary: Improved varieties of hard red spring wheat are necessary to respond to changing disease pressure and provide growers with high-yielding varieties that will be accepted in the marketplace. Traits with complex inheritance are difficult to improve with conventional breeding procedures. The purpose of this project is to conduct a comprehensive breeding program that aims to develop improved varieties of spring wheat. Basic research will be conducted to improve upon the breeding methods currently used. Expected economic impacts include improved return per acre for wheat producers, and greater economic stability for regions of the state that grow wheat. Wheat varieties with improved disease resistance should reduce the use of fungicides, thus resulting in potential environmental benefits. <P> Approach: A modified bulk breeding method will be utilized to develop superior spring wheat cultivars and germplasm. Most of these crosses will involve elite germplasm from the U of M hard red spring breeding program and germplasm containing new genes for high priority traits. Emphasis will be placed on crossing with germplasm containing potentially new genes for FHB resistance, leaf rust resistance, stem rust resistance to race Ug99, and enhanced bread baking quality or other unique grain quality components. Intensive screening for reaction to leaf rust and stem rust will occur in the F2, F4, and F6 generations. The F2 and F4 generations will be grown in plot areas that contain susceptible spreader rows inoculated with the stem rust and leaf rust pathogens. In addition, all materials in the preliminary yield trial stage or later are grown in a rust nursery managed to produce high levels of disease. Scientists (J. Kolmer and Y. Jin) in the USDA-ARS Cereal Disease Laboratory maintain and distribute inoculum and record reaction of materials in the rust nursery. Screening for reaction to Fusarium head blight will be a major component of the wheat improvement project. Scientists in the Plant Pathology Department (R. Dill-Macky and C. Hollingsworth) produce and distribute inoculum and help with recording disease evaluations in the field nurseries. End-use quality will be evaluated beginning with grain harvested from the F6 nursery and every generation thereafter. Grain samples of F6 lines selected for acceptable agronomic appearance, seed color/size/shape, and disease reaction (FHB nursery in St. Paul and other diseases as they appear at Crookston and St. Paul) will be analyzed for test weight, grain protein content, grain size and hardness, milling yield, and flour mixing properties at the USDA-ARS Wheat Quality Laboratory in Fargo, ND. Grain samples of all materials in preliminary and advanced yield trials will be sent to the USDA-ARS lab for the same measurements of end-use quality as listed above in addition to bread-making characteristics. The main focus of spring wheat germplasm enhancement in the next five years will be the continued development of FHB resistant materials adapted to Minnesota. Materials with high levels of FHB resistance, regardless of their status in the breeding program, will be re-screened in field nurseries the following year to confirm that they have high levels of resistance. Superior materials will be used as crossing parents and may also be released as germplasm and/or be used as a parent for subsequent gene mapping research. DNA marker technology will be used to locate genes influencing traits that are difficult to manipulate using conventional breeding and selection procedures or when gene pyramiding is desired. The main focus will be on mapping genes for FHB, leaf rust, and stem rust resistance, and preharvest sprouting in the next five years and using these genes in a marker-assisted selection program to effectively introgress them into elite germplasm. This research will provide training opportunities for graduate students and postdoctoral associates and will be supported from other sources of funding.