Identification of quantitative trait loci useful for Iron and Zinc biofortification in rice (Oryza sativa L.)

Date

6-2018

Abstract

Biofortification is one of the sustainable and cost-effective approaches for addressing iron (Fe) and zinc (Zn) deficiencies which are among the most common nutritional disorders worldwide. Marker-assisted selection, as an aid to phenotypic screening, can help in more precise and faster development of high Fe and Zn rice varieties. This study aimed to identify QTLs, candidate genes, and linked molecular markers for high grain Fe and Zn concentration using MAGIC Plus, DH, and RILs rice populations through GWAS and QTL mapping approaches.

Phenotypic analysis results showed consistent positive correlations between Fe and Zn and consistent negative correlations between YLD and Zn irrespective of populations and seasons. Several high Zn and high yielding lines from each population were further identified. GWAS detected 35 QTLs in the MAGIC Plus population and 1CIM detected 26 QTLs and 27 QTLs in the DH and RILs populations, respectively, for agronomic yield, and Fe and Zn biofortification traits. These main effect QTLs explained 7.0% to 37.1% of phenotypic variance. Consistent Zn QTLs on chromosomes 5, 7, and 12 co-located with Fe QTLs. Moreover, several candidate genes for grain element concentration were identified such as ZINC TRANSPORTERs (OsZIPs), NICOTIANAMINE SYNTHASE 3 (OsNAS3), NATURAL RESISTANCE-ASSOCIATED MACROPHAGE PROTEIN 7 (ONRAMP7), VACUOLAR IRON TRANSPORTER 1 (OsVITI), and metallothionein genes. This research highlights Fe and Zn QTLs, candidate genes, and molecular markers for further validation and molecular characterization that may prove useful in biofortification breeding.

Document Type

Dissertation

Degree

Doctor of Philosophy in Plant Breeding

College

Graduate School (GS)

Adviser/Committee Chair

Jose E. Hernandez

Co-adviser

B.P. Mallikarjuna Swamy

Committee Member

Merlyn S. Mendioro, Ma. Genaleen Q. Diaz, Antonio G. Lalusin

Language

English

En – AGROVOC descriptors

ORYZA SATIVA; LOCI; QUANTITATIVE TRAIT LOCI; IDENTIFICATION; IRON; ZINC; BIOFORTIFICATION

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