(P44-24-26) Developing a Genetic Strategy to Breed for Bioaccessible Provitamin A in Sorghum

Objectives: To characterize genetic factors contributing to variation in sorghum carotenoid bioaccessibility and its feasibility as a breeding target

Methods: We used an in vitro digestion method (Dzakovich et al., 2023) to quantify relative bioaccessibility and bioaccessible content of sorghum grain carotenoids. Using a diverse panel representing global sorghum genetic diversity, we identified a significant range of variation in carotenoid bioaccessibility traits. Building on initial findings, we 1) evaluated a subset of accessions in multi-location trials to determine genotype by environment (GxE) interaction effects on carotenoid bioaccessibility traits; 2) developed a biparental family from medium- and high-carotenoid parental lines to identify putative QTL underlying these traits; and 3) quantified potential inhibitor compounds to gain insights into factors contributing to reduced carotenoid bioaccessibility.

Results: We identified genetic markers associated with significant variation for carotenoid bioaccessibility that can potentially be used to help breed for provitamin A content and identified associations between bioaccessibility and inhibitors of bioaccessibility across environments.  Also we found that selecting for the ratio of 𝛼- to β-branch carotenoids to direct metabolic flux into the β-branch may be a more robust breeding strategy than selecting for total carotenoid content, since β-branch products likely have higher vitamin A conversion rates and their flux is more heritable and stable across environments.

Conclusions: This study demonstrates the potential to enhance bioaccessible carotenoids through breeding and identifies QTL to support marker-assisted selection in sorghum breeding programs to breed for biofortification.

Funding Sources: This work is supported by the U.S. Department of Agriculture’s National Institute of Food and Agriculture Foundational Knowledge of Plant Products, project award no. 2022-67013-36441, and by the Gates Foundation through the grant “Green Evolution - Accelerating Dryland Cereals Improvement for Africa" (INV-053669).  Additionally, the United States Department of Agriculture Agricultural Research Service (USDA-ARS) funded the Arkansas Children’s Nutrition Center through project plan #6026-10700-001-018-S.