Effects of S₁ Recurrent Selection for Provitamin A Carotenoid Content for Three Open‐Pollinated Maize Cultivars

Abstract

ABSTRACT Maize ( Zea mays L.) cultivars with increased concentrations of provitamin A (proVA) carotenoids can improve the health of millions of consumers who are vitamin A deficient and rely on maize as a staple food. Three open‐pollinated maize cultivars (OPC) were subjected to three cycles of S1 recurrent selection for increased proVA concentration. Agronomic performance of Cycles 0, 1, 2, and 3 for each OPC was evaluated using three replications at 10 locations, and changes in proVA concentration were assessed for hand‐pollinated grain produced at two sites. Selection resulted in significant ( P < 0.01 for 11, and P < 0.05 for 1 occurrence) linear increases of 25 to 67% per cycle for total proVA, 28 to 60% for β‐carotene, 18 to 70% for β‐cryptoxanthin, and 11 to 46% for zeaxanthin. These findings are especially significant because, in contrast to recent trends, they demonstrate the feasibility of developing proVA‐enhanced maize while meeting nutritionists’ recommendations not to sacrifice β‐cryptoxanthin and zeaxanthin to increase β‐carotene concentration in grain. Grain yield increased in one but decreased ( P < 0.01) in two of the OPCs, and we hypothesize that linkage drag associated with proVA‐enhancing genes from exotic donor lines may be responsible for the negative trends. We conclude that breeding proVA‐enriched maize without sacrificing β‐cryptoxanthin and zeaxanthin concentrations is feasible, but that (i) it remains unknown whether such approaches can achieve the high concentrations of proVA reported elsewhere by using marker‐assisted selection for genes that favor β‐carotene accumulation, and (ii) that grain yield and agronomic performance should be simultaneously selected if useful cultivars are desired.