Off-campus UNL users: To download campus access dissertations, please use the following link to log into our proxy server with your NU ID and password. When you are done browsing please remember to return to this page and log out.
Non-UNL users: Please talk to your librarian about requesting this dissertation through interlibrary loan.
Selecting Bread Wheat for Decreased Cadmium Concentration in Grain
The consumption of cadmium (Cd) contaminated food adversely affects human health. Heritable variation for the propensity to accumulate Cd in the grain exists, but is a difficult selection target, given the practical limitations of breeding operations. The objectives of this research were to assess the feasibility and efficiency of selecting low-cadmium lines 1) during grain filling using cadmium concentration in terminal tissues; 2) during seedling stage using shoot Cd concentration and using SNP markers associated with grain Cd concentration. Two high-Cd cultivars, ‘Freeman’ and ‘Wesley’, and two low-Cd cultivars, ‘Panhandle’ and ‘Overland’ were planted in Mead, Nebraska in 2014 and 2015. Grain Cd concentration in the terminal tissues of the four cultivars were measured during grain filling. Cadmium concentration in grain at 3 and 4 weeks after average anthesis (WAAA), in rachis at 2, 4 and 5 WAAA, and in the terminal vegetative node at 3 and 4 WAAA separated high- and low-cadmium cultivars, which indicated the possibility for selecting low-Cd lines during grain filling period. Low- and high-Cd lines were selected using shoot Cd concentration of two-week-old seedlings and grain Cd concentration associated SNP markers independently in a F4:6 RIL population derived from a cross between a high Cd accumulating line, ‘Wesley’, and a low Cd accumulating line, ‘Panhandle’. The RIL population was planted in Mead and Clay Center in Nebraska during the growing season of 2016-2017 and evaluated for grain mineral concentrations. Both the selection using shoot Cd concentration and the selection using SNP markers were effective in selecting low-Cd lines, but the SNP marker-based selection was more effective and less time and labor consuming. For better allocating resources and increasing selection gain per generation, breeders could eliminate the high Cd lines at seedling stage using the SNP markers and make additional selections in the field using Cd concentration in terminal tissues during grain filling.
Liu, Caixia, "Selecting Bread Wheat for Decreased Cadmium Concentration in Grain" (2018). ETD collection for University of Nebraska-Lincoln. AAI10845164.