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Genome-wide association studies of grain yield and quality traits under optimum and low-nitrogen stress in tropical maize (Zea mays L.)

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Title Genome-wide association studies of grain yield and quality traits under optimum and low-nitrogen stress in tropical maize (Zea mays L.)
 
Creator Ndlovu, Noel
Spillane, Charles
McKeown, Peter C.
Cairns, Jill E.
Das, Biswanath
Gowda, Manje
 
Subject genes
grain
nitrogen fertilizers
plants
sustainable development
tropical zones
genetic gain
maize
soil
genetics
biotechnology
 
Description Soils in sub-Saharan Africa are nitrogen deficient due to low fertilizer use and inadequate soil fertility management practices. This has resulted in a significant yield gap for the major staple crop maize, which is undermining nutritional security and livelihood sustainability across the region. Dissecting the genetic basis of grain protein, starch and oil content under nitrogen-starved soils can increase our understanding of the governing genetic systems and improve the efficacy of future breeding schemes. An association mapping panel of 410 inbred lines and four bi-parental populations were evaluated in field trials in Kenya and South Africa under optimum and low nitrogen conditions and genotyped with 259,798 SNP markers. Genetic correlations demonstrated that these populations may be utilized to select higher performing lines under low nitrogen stress. Furthermore, genotypic, environmental and GxE variations in nitrogen-starved soils were found to be significant for oil content. Broad sense heritabilities ranged from moderate (0.18) to high (0.86). Under low nitrogen stress, GWAS identified 42 SNPs linked to grain quality traits. These significant SNPs were associated with 51 putative candidate genes. Linkage mapping identified multiple QTLs for the grain quality traits. Under low nitrogen conditions, average prediction accuracies across the studied genotypes were higher for oil content (0.78) and lower for grain yield (0.08). Our findings indicate that grain quality traits are polygenic and that using genomic selection in maize breeding can improve genetic gain. Furthermore, the identified genomic regions and SNP markers can be utilized for selection to improve maize grain quality traits.
 
Date 2022-12
2023-01-05T09:16:45Z
2023-01-05T09:16:45Z
 
Type Journal Article
 
Identifier Ndlovu, N., Spillane, C., McKeown, P. C., Cairns, J. E., Das, B., & Gowda, M. (2022). Genome-wide association studies of grain yield and quality traits under optimum and low-nitrogen stress in tropical maize (Zea mays L.). Theoretical and Applied Genetics. https://hdl.handle.net/10883/22323
1432-2242
https://hdl.handle.net/10568/126603
https://hdl.handle.net/10883/22323
https://doi.org/10.1007/s00122-022-04224-7
 
Language en
 
Rights CC-BY-4.0
Open Access
 
Format application/pdf
 
Publisher Springer Science and Business Media LLC
 
Source Theoretical and Applied Genetics