Location: Grain Quality and Structure Research
Project Number: 3020-43440-002-030-S
Project Type: Non-Assistance Cooperative Agreement
Start Date: Sep 1, 2022
End Date: Aug 31, 2026
Objective:
The objective of this project is to identify alleles regulating sorghum grain quality characteristics (starch, protein, fat, and lysine) with a minimal harvestable yield tradeoff. Molecular markers will be developed to facilitate grain sorghum breeding to meet different market needs based on specific grain quality profiles.
Approach:
The goals of this project will be achieved through three Specific Objectives:
Specific Objective 1: Identify key genes controlling major grain quality traits (starch, protein, fat, lysine). We have assembled a library of plants having mutations in each candidate gene of starch, protein, fat, and lysine physiological networks (based on the maize and rice literature). These are perfect materials to test gene functions and physiological tradeoffs among different grain quality pathway alleles (e.g. to study tradeoffs between protein and starch synthesis). Both reverse and forward genetics approaches to validate key genes controlling sorghum grain quality using a mutant population in the Tx623 genetic background.
Specific Objective 2: Identify superior combinations of yield and quality alleles for different market needs. Due to the potential for genes to have multiple functions in plant development, an allele that maximizes (for example) grain protein content on a per-seed basis could reduce harvestable protein yield on a per hectare basis. The genetic basis for any potential tradeoffs between seed contents and harvestable yields of protein, starch, fat, and lysine must be understood to support commercial hybrid development and local adaptation. We will perform a Genome-Wide Association Study (GWAS) to identify loci impacting the tradeoff between each nutritional biomolecule’s content in seeds and its harvestable yield.
Specific Objective 3. Develop molecular markers and screen core breeding population. Breeder-friendly molecular markers will be designed to facilitate making selections for grain quality and harvestable yield and published. A Grain Quality Core population having the highest protein, starch, fat, and lysine contents will be selected using the markers and publicly released. Results will enable marker-assisted selection for different grain chemistry profiles by public and private breeding programs. They will also enable the development of genomic selection methods for superior parental lines in future grant proposals submitted by our research team.
