Association Mapping of Carotenoid Candidate Genes and CO2 Assimilation in Sorghum.

Carotenoids are a group of pigments with diverse biological functions. In leaves, they are components of the light harvesting complexes and involved in photo-oxidative protection when light is in excess and cannot be transformed into chemical energy. In sorghum, a “carotenoid diversity panel” was assembled to study the association between carotenoid genes and accumulation of pigments in the grain for human consumption. The same panel was used in this study, and the genotypic information available for twelve carotenoid candidate genes was associated with C assimilation and non photochemical quenching, using LI-COR 6400XT under greenhouse conditions. The twelve carotenoid candidate genes include: Crtiso, Lcye, Crtrb1, Crtrb2, Zds, Ccd1, Ccd4, Lcyb, Crtre, Pds, Psy1 and Psy3. This research had three major goals: a) determine the level of variation in C assimilation rates in a carotenoid diverse set of sorghum germplasm that could positively affect yield; b) determine the level of variation in photoprotection in a carotenoid diverse set of sorghum germplasm that could positively affect yield under stress conditions; and c) establish the level of association between carotenoid genes and C assimilation/photoprotection by Linkage disequilibrium (LD) mapping. Results from this study have the potential to impact sorghum yields and yields under abiotic stress conditions.