AUTHOR=Ashokkumar Kaliyaperumal , Govindaraj Mahalingam , Karthikeyan Adhimoolam , Shobhana V. G. , Warkentin Thomas D. 

TITLE=Genomics-Integrated Breeding for Carotenoids and Folates in Staple Cereal Grains to Reduce Malnutrition

JOURNAL=Frontiers in Genetics

VOLUME=Volume 11 - 2020

YEAR=2020

URL=https://www.frontiersin.org/journals/genetics/articles/10.3389/fgene.2020.00414

DOI=10.3389/fgene.2020.00414

ISSN=1664-8021

ABSTRACT=Globally, two billion people suffer from micronutrient deficiencies. Cereal grains provide more than 50% of the daily requirement of calories in human diets, but often fail to provide adequate essential minerals and vitamins. Cereal crop production in developing countries achieved remarkable yield gains through the efforts of the Green Revolution (117% in rice, 30% in wheat, 530% in maize, and 188% in pearl millet). However, modern varieties are often deficient in essential micronutrients compared to traditional varieties and land races.  Breeding for nutritional quality in staple cereals is a challenging task however, biofortification initiatives combined with genomic tools increase the feasibility. Current biofortification breeding activities include improving rice (for zinc), wheat (for zinc), maize (for provitamin A) and pearl millet (for iron and zinc). Biofortification is a sustainable approach to enrich staple cereals with provitamin A, carotenoids, and folates. Significant genetic variation has been found for provitamin A (96 to 850 µg and 12 to 1780 µg in 100 g) of wheat and maize, respectively, for carotenoids (558 to 6730 μg) in maize, and folates in rice (11 to 51 μg) and wheat (32.3 to 89. 1 μg) in 100 g. This indicates the prospects for biofortification breeding. Several QTLs associated with carotenoids and folates have been identified in major cereals, and most promising of these are presented here.  Breeding for essential nutrition should be a core objective of next-generation crop breeding. This review synthesizes the available literature on folates, provitamin A and carotenoids in rice, wheat, maize and pearl millet, including genetic variation, trait discovery, QTL identification, gene introgressions, and the strategy of genomics-assisted biofortification for these traits. Recent evidence shows that genomics-assisted breeding for grain nutrition in rice, wheat, maize and pearl millet crops have good potential to aid in the alleviation of micronutrient malnutrition in many developing countries.