Breeding for Grain Quality Traits: The Challenges of Measuring Phenotypes and Identifying Genotypes

An introduction to methods and difficulties of plant breeding. Comparisons are made between corn, proso millet, wheat, and sorghum. Lesson Objectives This lesson is an introduction to methods and difficulties of plant breeding. Comparisons are made between corn, proso millet, wheat, and sorghum. After completing this lesson you should be able to: Distinguish between plant breeding and seed production. List some different types of grain quality traits targeted by plant breeders. Describe the range of methods the plant breeders may use to measure grain quality traits and rank their relative difficulty. Describe the types of genetic control observed for different grain traits. Assess the impact of the following factors on the workload and success a plant breeder might expect in their breeding program: (a) method of trait measurement, (b) role of environment on trait variation, (c) genetic control of the trait variation, and (d) mating system of the crop species. Four plant breeders—Steve Baenziger, David Baltenspurger, Jeff Pedersen, and Ken Russell—breed different grain crops grown in Nebraska. A common goal in their work is discovering varieties of their crops (wheat, proso millet, sorghum, and corn, respectively) that will produce high grain yields. An additional concern is grain quality. Quality can involve traits that are as obvious as grain color or as subtle as phosphorus levels. Adding grain quality traits to the required characteristics of a crop variety imposes many new challenges for these plant breeders. This lesson describes two major questions plant breeders will address in their work as they alter a grain quality trait in a variety with acceptable yield. The first is “how will they measure the trait and select the plants they want?” The second is “if they find plants with the desired quality trait, how is that trait genetically determined and how will it be passed on?” The answers to both questions will determine the amount of work it will take to accomplish their goals. Modules: Lesson home Lesson Objectives The R & D and Manufacturing of the Seed Industry Work of the plant breeder part 1: Measuring Phenotypes: The work of the plant breeder part 2: Finding the right genotypes: Genotype vs. Environment Genotype by environment interaction Simple inheritance of grain quality traits Complex inheritance Gene action Recessive you know, dominant you don’t Dominance or a lack of dominance Maternal traits vs. biparental traits The work of the plant breeder and producer: Glossar