Phenotypic characterization and validation of provitamin A functional genes in early maturing provitamin A-quality protein maize (Zea mays) inbred lines.

Ebenezer Obeng-Bio,Agyemang Danquah,Mustapha Abu Dadzie,Baffour Badu-Apraku,Beatrice Elorhor Ifie,Essie T Blay

doi:10.1111/pbr.12798

Abstract

The number of drought and low‐N tolerant hybrids with elevated levels of provitamin A (PVA) in sub‐Saharan Africa could increase when PVA genes are optimized and validated for developed drought and low‐N tolerant inbred lines. This study aimed to (a) determine the levels of drought and low‐N tolerance, and PVA concentrations in early maturing PVA‐quality protein maize (QPM) inbred lines, and (b) identify lines harbouring the crtRB1 and LcyE genes as sources of favourable alleles of PVA. Seventy early maturing PVA‐QPM inbreds were evaluated under drought, low‐N and optimal environments in Nigeria for two years. The inbreds were assayed for PVA levels and the presence of PVA genes using allele‐specific PCR markers. Moderate range of PVA contents was observed for the inbreds. Nonetheless, TZEIORQ 55 combined high PVA concentration with drought and low‐N tolerance. The crtRB1‐3′TE primer and the KASP SNP (snpZM0015) consistently identified nine inbreds including TZEIORQ 55 harbouring the favourable alleles of the crtRB1 gene. These inbreds could serve as donor parents of the favourable crtRB1‐3′TE allele for PVA breeding in maize.

Highlights

Maize production in sub-Saharan Africa (SSA) is limited by drought and low-N which are the two most frequent yield reduction factors in the sub-region (Badu-Apraku, Fakorede, Oyekunle, & Akinwale, 2011)
The significant variability among G for grain yield and most of the traits measured under each and across test environments implied the existence of genetic variability in the early maturing provitamin A (PVA)-quality protein maize (QPM) inbreds
The significance of E and GEI observed for grain yield (GY) and several other traits under each and across environments suggested the inconsistent rankings of the traits measured in varying environments and that inbred evaluations in more environments were necessary to identify outstanding cultivars under drought (Badu-Apraku et al, 2011; Edmeades, 2013) and under low-N (Meseka, Menkir, Ibrahim, & Ajala, 2006)

Summary

Introduction

Maize production in sub-Saharan Africa (SSA) is limited by drought and low-N which are the two most frequent yield reduction factors in the sub-region (Badu-Apraku, Fakorede, Oyekunle, & Akinwale, 2011). Studies have revealed that genetic improvement in maize for stress tolerance could result in genetic gains under drought (Badu-Apraku et al, 2011; Edmeades, Bolaños, Chapman, Lafitte, & Bänziger, 1999) and under low-N (Badu-Apraku, Oyekunle, Akinwale, & Aderounmu, 2013). Vitamin A is an essential micro-nutrient required by human beings for improved eye sight and enhanced immune system. Humans must consume either vitamin A or provitamin A (PVA) carotenoids, from which we synthesize vitamin A. The PVA maize has the potential of supplying more than 15.0 μg/g dry weight (DW) PVA which is the set target to combat vitamin A deficiency (VAD) especially among children and women when common amounts of PVA maize are consumed compared to just about 2.0 μg/g DW found in

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Conclusion